Since recent Yamaha arrangers have an option to download new voices, it’s harder to justify buying a whole new keyboard.
So I can speculate that Yamaha has to rethink the whole concept of PSR; it seems reasonable that they will rebrand it just like they did with Tyros and Motif, and we’ll see a touchscreen and less buttons on a panel. Otherwise whatever they do it will be too close to what we already have.