firefoxos wasn’t centered around ffox, just the brand + a choice to make HTML/javascript/web the prime developer framework instead of Java/ObjC. But (among other problems) turns out that framework has a lot of rough edges for that use case. And has zero compelling features for switchers.

Meh. Your conclusiveness that this was awful & in zero ways compelling & not good lacks evidence. Whats the opposite of survivorship bias? Failure anti-bias? It's not true. It's crap.