FirefoxOS gets a lot of hate, but I honestly thought it was a pretty good idea. The problem was that it was terribly executed.
It’s a bit unclear to me wether that was your point or not.
I think what OP was saying is that Mozilla is so poorly managed that they took a great idea and made it crash and burn.
Firefox OS was abandoned pretty quick as I remember, 2 years tops?
I would not single that out as a failing.
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.
It never works.
Sometimes you need to plough your way through the field to get the bountiful harvest - Mozilla did that and then left the harvest to burn.
A thing can be good and successful without being the global leader, unless you want monopolies for everything.
Then hardware manufacturers started producing cheap hardware that could run Android with acceptable performance, thus eliminating the price advantage for FirefoxOS, before that OS could take off in third world nations.