I once read an interesting theory on that. Basically, Marvel doesn't really care about comic sales anymore - they're peanuts compared to what they're making on their movies. Rather than try to tell interesting and well-written stories to make a little more chump change, they're using their comics division to aggressively earn progressive brownie points. This way, they have something to point to when people start complaining that the Marvel movies don't have a lot of women and minorities in them, because that shit doesn't sell in China.
I don't really think that's what's going on, but I thought it was an interesting take on it.