I know Thompson can handle 3 books a month. She's been doing it for the better part of the past year or so. While writing both Jem and Hawkeye, she also did A-Force, and after that wrapped up, she had a Misfits mini. And now that she's moved on from Jem, she'll presumably need a new major ongoing project, and I think Invincible Iron Man would be a great place for her.
Wilson seems less able or willing to do two books at once on an ongoing basis. Which is a shame.
As for women wanting to do something other than cape comics, I mean, no, a lot of them love cape comics. A lot of them are capable of writing cape comics and creator-owned comics at the same time. It is true that there are female creators who don't particularly want to do cape comics, but given how the industry treats them, can you blame them? They know they're not going to get any respect in mainstream comics. They know they'll never get to write Captain America or Amazing Spider-Man, outside Annuals and back-ups and the like. They're going to be kept in the sidelines, not given the same opportunities male creators get. So of course they decide to just say "screw that" to the major publishers and make their own opportunities.