I think they'll keep the main games going for the prestige alone. Despite XV's issues, the game has already sold close to 8 million units of which if they only received half of the game's cost, made them close to $200 million dollars, so it's not like the game was a financial failure, and has likely already made back most of it's costs.
EDITGA: I've been doing some research about Tabata's time at SE which lead to reading up on the development of some of his titles, and now I don't feel like the idea he quit because SE kind of dumps on him all the time is too far fetched.
He got drafted into working on 3rd Birthday while he was working on Type-0 his first game that could argued to be completely his, and SE nearly cancelled it so he would focus on 3rd Birthday instead. When he was asked to come onto the Versus XIII/XV project, he apparently found the game in such a bad spot development-wise that not only was SE's president considering cancelling that title and just starting over, but the Type-0 team didn't want anything to do with the project and Tabata had to convince them to sign onto it, and we now how that went.
As someone who has been dragged into troubled productions before, I can feel his pain.