This is all true. This will happen, film will move out of the commercial market, but again, I like that. I see kids who are digging film more than they do digital. I met DPs in their 20s who just love film and they shoot film whenever they have a chance. Sure, the commercial clients will ask for the latest technology. That has always been the case. And while, as you rightly put, 16mm will become a niche market, but it already is. One of the best new exhibitions I've seen recently (In ICA London) which got big praise, has been shot and projected entirely on 16mm.
So,it will preserve its dignity and the value of cameras will again go up a bit, but eventually, it will never be extremely expensive. More importantly, the value will stay stable. Here in UK, you can't find Super 16mm Bolex for under 1k. And that is without the lenses. So, I don't know. We'll see, but in essence, I agree with everything you wrote, it is just that I'm not too worried about the commercial market. I know the aesthetic value of film. If someone can't see it, that is his or hers problem. It's the same argument one can have about hi-fi gear. Is it justified to buy valve amp from the 80s or to buy the whole new set with GPS. :)