I actually think that when they say "it's not worth it" it's not a matter of money, but a matter of time.
Projects like this one, with hundreds of staff, need a ton of bureaucracy, since the more people work, the less actual freedom they have, since they need to be more structured.
Let's say that i'm an animator, or whatever, and I want to add a woman to the coop, how long is it going to take? including compilation, bug checking, QA and all that? six hours? a day? dunno.
But then, these six hours that I was working on that, are six hours that I wasn't free to help that other guy on that whatever thing we were scheduled to do months ago, and so we won't be able to help in that another thing, and so on and so on.
Even a change of one day in the release date of a game is a lot of money lost, they'll need to tell all the millions and millions and people who were waiting to buy that game day one, why they'll need to wait one more day (and they outnumber the people who care about woman in coop by at least 50:1), they'll have to talk to all of the stores, and buildings, and whereever they already payed millions to to have their commercials on the right time and so on.
So what's the problem? Just hire another animation guy/girl for this!
Again, not that simple, but i'm too damn lazy to explain why I think that is.