[TootsMagoon]

ELI5: Why would a team of developers and investors work on something with such a small chance of becoming a viable market?

Honest question. Not intending to be snarky. Reminds me of the many Chrome knock-offs that focused on a particular aspect of browsing. Any advancement/advantage would be quickly adopted by the mainstream market leaders.

[tom_mellior]

There are a bunch of native Sailfish OS apps. As far as I can tell, people work on them for fun, not for the expectation of making money off of them. For users, the result is not necessarily bad: Unlike many free Android apps, there are no annoying ads. And there are actual OpenStreetMap apps that simply use the online map data, unlike OsmAnd, which makes you pay for access to maps they didn't create.

An enormous amount of open source development on Linux is not driven by a "market" in the sense of making money either. This doesn't answer your question directly, but maybe the question is ill-posed. Do we want or need a "viable market" that looks like crappy ad-infested Android bloatware?

(Just to be clear, no, I am not saying that all Android apps are alike.)