Its either camera-brands making apps or Apple that start making high-end camera's... which one will come first.
My bet is Apple
My bet is Apple
Casual users who care about apps will just use their phones and the quality will be on par with Micro-4/3 and likely APS-C with computational photography advances.
Prosumers will stick with smaller full frame optimised for style and old school usability e.g. Leica. Professionals will either use full frame for speed or move towards medium format which Fuji is leading the charge towards.