Microsoft made a new OS where they needed developers to target their platform. Too few did, and the platform failed.

Mozilla tried to bypass this chicken-and-the-egg problem by being able to leverage PWAs which “everyone” is making anyway these days. It wasn’t a too crazy bet that it might have worked.

In a similar vein the Pinephone is trying something similar these days: not asking developers to target it, but instead leverage existing app eco-systems (Linux and web).

I don't expect a runaway mainstream success here, but I do wish them luck.