You are mistaken.
I started a firestorm on a board in 2008 by linking to the Bechdel test. It was a lot more underground then. Amy Bechdel herself said I'd brought more traffic to her site with that post than it ever had previously. And the discussion we had - industry folx, closed board - was vitriolic and passionate.
Yes, it's a joke - the point was Alien was the last movie to pass (this was in 1988 or so, when the test was first conceived) because it has two girls who talk about killing the alien. The point being, it takes next to nothing to pass, yet that level of normalcy (two female characters that do not exist solely as foils for male relationships) is still noteworthy in cinema.
It's switching, though, for the same reason anything switches in Hollywood: money. Teenaged boys are more likely to spend their evenings playing GTA than watching Pacific Rim and since there still aren't a lot of girl-friendly (let alone girl-centric) video games, Hollywood is attracting any audience they can.
Keep in mind - it's not about "strong female roles." It's about any two female roles doing anything other than talk about men ever. And no - there's no girls in The Hobbit. There's barely girls in LoTR. Jackson built them out a whole bunch, otherwise it would have been a massive sausagefest.
The arts are masculine. That's a fact. They're becoming more gender-neutral. That's also a fact. But expecting it to happen without turmoil is to expect disappointment.