I'm guessing that everybody's going to lose for a while.
When Netflix began offering streaming services, the major studios weren't certain enough that it would take off to develop their own, but they were willing to loan out their catalog, make some money off of licensing, and see how things played out. Netflix had a large and varied library, and it was available in one place for a reasonable price. Now that the model has been proven though, the pendulum's swung the other way and everybody's trying to start their own streaming service.
I really don't think the market can support this fragmentation, though. Best guess: after a few years of loss, media companies with B-list streaming services will decide it's just not worth it to maintain and decide to go back to licensing. In that case, all Disney has to do is weather the storm for a few years and then buy up enough other catalogs to become a real player (e.g. in my view, Disney = not worth a second look, but Disney + Sony + Star Trek from CBS = maybe).
