I think about stuff like this all the time, and this is what I've come up with.

First, sci-fi appeals to the ComicCon crowd that Hwood has been courting for sometime. It's generally that same smart, young(er), predominantly male audience, though I'm a big sci-fi fan (but I'm always a bit of an outlier.)

Second, and more importantly, all of our lives are more entwined with tech than ever and this is a trend that is only growing. The constant interaction with digital technology is literally changing our brains, and I expect what those brains then resonate with in terms of story is changing, too. Not that we aren't going to be interested in character arcs and archetypes and the hero's journey and all that tried and true stuff, but that we're more interested in seeing stories where tech is a major part of the world because it's a major part of ours. Sci-fi fits this bill, and in this respect -- the portrayal of a world where technology is an omnipresent given -- sci-fi is actually more realistic than stories set in this day and age that ignore the impact of technology completely, as if that same story could be lifted up and slapped down in 1980 without a hitch.

One word answer: Avatar.

Science fiction films require a great deal of world building. If you can write a great spec set in a great "world" that gives studios a shot at a franchise. The three most "franchiseable" (if that's close to being a word) are 1) comedy 2) horror 3) science fiction. Of those three, sci-fi really has the ability to draw large audiences.

I agree that "Avatar's" success has a lot to do with it too.

I expect Avatar did have an effect. But my feeling is that the (largely unexpected) worldwide success of Inception - a complex, intellectual, high concept movie, exactly the kind of sci-fi that most pundits would say never sells to a mass audience - has a lot more to do with it. One success creates an appetite for more of the same...

Here are my theories:

1.) Sci-fi is the new Western. I was thinking about this while watching "High Noon". The old Western genre was such a great way of telling all sorts of stories of heroes and villains. The old West town was a symbol -- a microcosm of the larger world -- and writers took advantage of this. Nowadays when a story is set in the old West the writer is going for realism and not so much using the genre as a metaphor. Which leads to something I remember Rod Serling once said about storytelling and television (don't think this bit has appeared in your clips). He said when he originally pitched some ideas to the network they were taken aback by the political nature of the stories and rejected them. He rewrote them as sci-fi (changing politicians to aliens or some such thing) and -- what do ya know? -- the networks went with it. Sci-fi allows a writer the freedom to tell stories that may otherwise be deemed subversive if told straight.

2.) CG special effects have progressed to the point where it is feasible to shoot a movie about a mega shark and a giant octopus and not have the production values look totally hokey (okay, almost not totally hokey.)

3.) Sci-fi is cool.

Definitely Avatar and Inception are HUGE players in that shift in the spec market this year. You saw it right after the success of Paranormal Activity, too: studios don't know the meaning of "lightning doesn't strike twice." They see lightning strike for a 15,000 dollar movie filmed in the directors home that grosses over 100 million (or whatever the exact number was), and they go Oh! Look! Paramount has a low budget franchise, we should try and make one too!

Similar thing happened with Inception, I think. Which really surprised Warners. They made Inception SOLELY to get Nolan to finish off the Batman trilogy--they didn't care if it bombed, because they knew it was going to get Nolan to direct a sure-fire billion dollar grosser for them next. Slightly cynical, perhaps, but you can see the motive.

A comment on what Annika said about the comic-con crowd. I think the fact that studios are buying sci-fi scripts is the fact that sci-fi, in the past two years, has proven able to attract people OTHER than the comic-con crowd. Because the Comic-Con crowd is a huge minority, really. Extremely loud and extremely visible at certain times, but they're a minority. And, almost every single movie that comes riding out of Comic-Con with enormous hype that's not a sequel or part of a franchise has failed to meet whatever massive expectations it had when the fanboys gushed over it. Partially because they were the only demo that actually showed up in theaters.

Avatar and Inception appealed across the board, and the result was over 2.5 billion and over 800 million.

Planet of the Apes this year appealed to a much broader range of people than Cowboys And Aliens did--if you compared tracking numbers and exit polls for those, Apes would be FAR more diverse--and look at the difference in their grosses.

So. I think the most important factor for studios finally cracking open the wallet for big sci-fi spec purchases has the most to do with the fact that they feel like they have enough evidence that the sci-fi genre has started to appeal to far more than just the comic-con crowd.

I agree that sci-fi appeals to far more than the Comic Con crowd, but stand by thinking that that Hollywood is still wooing the Comic Con bunch, for whatever reason. You see it in the kinds of TV shows getting greenlit, too. Perhaps it's because they're so vocal and Internet savvy, perhaps it's because they are largely male and under 40, perhaps it's because they tend to spend money on subsidiary products tied into films, perhaps it's for all of the above reasons, but the Comic Con crowd has held a disproportionate amount of sway over Hollywood's imagination for the past three years or so, where other audiences (hello, Bridesmaids!) have been largely overlooked, but this past summer could change that trend. I feel the rest of the world has moved on and realizes there are other demographics out there, but Hollywood execs are largely lagging in this respect.

Every one in the comments has made some really good points but I think some other factors are being overlooked. The most obvious and unhelpful to screenwriters is that the market is cyclical and different genre's will be in demand at different times because of a confluence of creative forces being attracted to the genre.

However there are some more concrete factors to consider. One that has already been discussed here is the Comic-Con demographic. I agree with the other commenters here that you can dismiss them with regards to opening weekend B.O. numbers but that isn't the only thing this audience is good for.

Comic-Con "fanboys" for the lack of a better word are notorious for being extremely passionate about a story or "property" they love. The kind of person that is passionate about a particular genre is exactly the same person that makes cult-classics. They're the fans that will return for repeat viewings at a theater. They will tell all their like minded friends about it. In other words they will give the film legs.

They are also the people that will buy the DVD, the Blu-Ray, the special edition Blu-Ray, the collectors edition, the... I think you get my drift by now. They'll buy the comic, and the collectible figurine, and the poster, and the video game. OK I know I'm being hyperbolic but I just wanna emphasize that tickets aren't the only thing that the studio's are thinking about in terms of profit. The fact that they can sell ancillary merchandise to these fans is another huge motivator.

Now studios know that they can't make everyone of these Comic-Con movies a cross-over success but if they can find one movie, one movie that combines fanboy enthusiasm with widespread appeal they'll have the holy grail of studio blockbusters: another Star Wars.

The other factor to consider in today's modern times is the ability to realize these often outlandish concepts more convincingly and with less money than ever before. If you haven't already seen Monsters than you might wanna look it up. The fact that one man could write, direct and do the special effects for $500,000 is ridiculous. Adam Sandler comedies cost more than that.

When someone knows they can realistically make those stories possible, it makes it easier to embark on writing one. A novelist has never had to consider the budget when they write of interplanetary travel, or battles with robots and perhaps that's why there's been a disparity between the output of science fiction between books and movies. With today's technologies that gap is closing and as huge fan of science fiction I am extremely excited.

Let's just try to write good ones and not just shameless knockoffs.

I recently noted this trend as well. The title was Sci-Fi Is The New Vampire.

I'd also like to add Moon to the list of influences. Release dates in this trend continue into 2014.

I believe that since a Sci-Fi exists in its own world without any historical, cultural or moral baggage it becomes more accessible to me as part of a ‘Global Audience’.

If you put it in perspective a movie about India and Pakistan fighting will require the audience to be familiar with at least 70 years of history. Tell the same situation between the fictional countries of Pancham and Droga in the year 2060 you get away with it.

Also I have seen the release of a Science Fiction film becoming an event here, an occasion for everyone to plan and go as a group to the only Imax in town which in Mumbai is a two hour drive one way.

I think it has a lot to do with the primetime network success of the show LOST. Once people like my 65 year old mother who never sat through a sci-fi anything in her life were puzzling over the mechanics of time-travel, I knew we were entering a new world for sci-fi. Unlike something like Avatar which was a totally by the numbers sci-fi adventure LOST brought these ideas to audiences that never saw or thought about them before. In it's wake we see Desmond/Pennyish sci-fi love stories like The Adjustment Bureau and Source Code bubbling to the surface. Just a guess.