But the subtext is that this is enough of a population to make a viable market, that in fact any number of people, however small, make a viable market. It's just not a reasonable prior.
So I'm asserting that it may as well be zero as far as the big manufacturers are concerned, that with such a small audience it's not profitable. Further, that this dynamic does indeed play out in other markets.
OP is looking for a conspiracy as to why phone manufacturers are leaving money on the table. The truth is they aren't. This situation is exactly what you'd expect when there's no real market - a few niche providers making a few niche products for die-hards (without the scale, support or quality of the majors) and not making a lot of money at it, while the rest of the market ignores them.