Sorry it's taken 5 pages for me to respond. I kind'a forgot this thread.
So the consensus seems to be:
1) DC has "translation problems" getting to the screen that Marvel doesn't have for some reason
2) Studio prejudice based on perceived lack of financial return.
3) Studio prejudice based on latent discomfort with strong female characters/misogyny.
That about cover it?
By the way, No mention of Laura Croft or Buffy as successful female led action offerings? Yes I know Buffy was primarily TV, but they have entire COURSES in college based on her now...