I can see FB/MS tapping into deep pockets to offer some top streamers a great deal to move platforms. If they get enough of them to move and the service is stable, intuitive and fun to be on then I can see FB doing well.
FB knows how to build communities, they know how to build engaging content and how to run that type of business. I would bet on them figuring out how to leverage their subject matter expertise on that side house to bring a very good product offering in this new vertical.
There’s an ecosystem there that they can tap into as well, marketplace, pages, etc that if they can pull it off, could make it a very lucrative all-in-one solution for the streamers.