I hear your concerns, I recognize your needs. I just don't see that rebasing the camera's software atop something more flexible & open-to-building-atop like for example Android would in any way pose a threat to the camera as you know & love it.
The fact is there's no reason you'd even have to know a camera is running Android. You can put whatever user-interface shell you want on to an OS, and it could run the same form factor, present the same (hopefully better) menus and interfaces & buttons, flip through menus just as fast, have the same optics, allow the same batteries. Get Micron or someone to use persistent memory so the boot time is even less than what you have now, which is not, as you say, instant, at least not on any camera I've ever seen.
New cameras like the Sony A7S iii have really good buttons-or-touchscreen interfaces. I think a lot of people have thought buttons are the way to go, have a die-hard perspective on what a proper camera is, but they, now that the future is here, are finding the flexibility offered amazing, finding that they would never want to go back.
> The idea of ruining a perfectly good system by pushing Android onto it ‘because apps’ or whatever it is such HN/disruptive nonsense.
The software defined world is one of open possibilities. "Because apps" is such a droll unimaginative slander of that notion. It's great that you feel so well served by your fixed-function cast-in-stone device, but it A) doesn't have to be that way forever, for every-one, and B) if cameras do get more flexible & capable of user-defined behaviors, it doesn't mean you have to lose this thing you evidently love.
Allowing people the flexibility to explore additional ways of doing photography seems to me like it should be obvious & is a frontier I look forward to opening.
I come from a different place. My friends are all pro-sumer, not professionals, but we're all insulted beyond belief how inflexible, how bad the computational photography is on our fancy mirrorless cameras, especially as compared to modern Pixel cameras. More-so, failure to start allowing more creative uses of cameras is an existential risk to cameras. Yes, some photogs will keep readily buying forever, but a lot of consumers find way more value from their phones, and cameras ought to want to be able to compete, to be devices for creativity. Right now, they are, but primarily inside the same lines they have been for decades on end now.
> This is exactly what most photographers want.
Not that big a market, compared to the rest of the world, who also enjoy taking photos, it turns out. But I think the photogs would be better served too, in the long run; much better served.
And I don't think they'd lose anything either.