Can't argue with himJake. A lot of us in here have been making the same gripe lately.
On my blog, I always to place the historical cutoff date at which point studios stopped looking for original scripts and started selling marketing "franchises"--
Where every hit movie was now a brand name, and movies were treated as bulk-serial episodes of hit TV series, where we were told to "Tune in next year, same Bat-month, same Bat-theater!"
Don't think it was just Marvel that Caused It, I'd go all the way back to the Great Screenwriter Bubble of 1988-91:
When studios tried hitch their wagons to hit action-movie screenwriters who could produce new original blockbusters on demand, causing a literal bidding-war of one-upmanship between Pen Densham, Shane Black and Joe Eszterhas, to see who could get the record-breaking highest price for "Prince of Thieves", "Basic Instinct" and "The Last Boy Scout".
When "Last Action Hero" finally popped the Bubble (like tulips and mortgage-derivatives, that's what happens when dreams push the price up too far...), studios began looking at ways they could start writing the Screenwriter out of the equation, since they were becoming the second-most expensive item after the already-expensive A-list star and CGI.
The by-product was, studios could now only afford to make movies audiences knew already, since you didn't need to hire anyone to risk profits by making up an unknown story--
When you see a teaser poster nowadays, the "tease" is a logo or character you already know, and the "sell" is, it's back again!
(I don't think that Marty's Asiaphilic remake of "The Mission" is going to rescue movies singlehandedly, but it would have been nice to see that alternate universe where enough voters had actually seen "Hugo" for it to win the Best Picture Oscar...)