Funny that you say Gravity didn't target baby boomers because it couldn't have been more on target. The formative years of the boomers was called — wait for it — The SPACE Age. And Bullock and Clooney are solidly part of that demographic.

I'd also add that those of us who grew up in the 80s, also want to see these films because these are the movie stars we grew up with. Seeing De Niro or Stallone brings back nostalgia and touches something in those of us who grew up watching these stars in the movies of our youth. So not only are they bringing in the Boomers, but us Gen Xers as well.

Best way to sum up this article: Clint Eastwood. In the past two decades he's been able to play/direct the same character that appeals to Boomers; tough, no nonsense badass with a moral compass. His characters like things simpler and consistant (the car from Gran Torino, older sports like boxing and baseball) and resists change.