If they put in a good CPU and use a standard OS, they would have more trouble selling you a new camera with newer features, since you could just upgrade your old one.
I have several replaceable-sensor cameras and the bodies/lenses were made before I was born. They still take great pictures because it turns out that focusing light onto stuff is largely a solved problem. (They don't even use batteries, much less need an up-to-date OS! But I will admit that carrying a separate light meter is a little annoying.)
Yes, there will always be people that need a 1 billion point autofocus system, and that will require some heavy software engineering. That is a niche use case, even more niche than needing a digital camera to begin with.