This is crystal ball stuff. Film will be around for a very long time yet given that digital constantly burns itself out with "the next best thing".
There will be ebbs and flows, not strictly marked rises and falls according to market demand, even if it is a niche market. I am not concerned about film where I am, though I and many others are concerned by the extraordinary disparity in prices that so far has not been adequately explained. Nothing to do with "supplying a shrinking market" or the like.