"The idea that Black wrote a spec script on pre-existing material -- the original rumor -- seemed pretty loopy."

i've heard this sentiment before. from my spec-monkey outsider perspective it seems perfectly natural to think shane black might have written a spec screenplay based on his own characters.

i manage it. doesn't he have the time? or is it that once you've been paid to do it you're no longer interested in writing on spec? was KKBB a spec script?

The issue isn't that Black wouldn't write a spec script -- The Last Boyscout, The Long Kiss Goodnight and Kiss Kiss Bang Bang Black wrote on spec. The 'loopy' aspect of it is why write a complete spec script about a pre-existing franchise? You, the writer, don't own the material anymore -- when you sell it, the studio obtains the copyright. So it's possible a spec script might excite a studio to resurrect a franchise, ala Lethal Weapon; however, it's also likely that it wouldn't, in which case the writer has spent months and months of writing to end up with a doorstop.

Or to put it another way, if a writer is going to go to all the time, effort, and hassle of writing a script on spec, why not write an original story with underlying rights that you control?

Just to be clear, I'm a big fan of spec scripts, even by working writers. You can write what you want to write, control every aspect of the story, and if you've got some heat and the script is good, it's possible to package that sucker into an eventual bidding war.