Today 10 years ago I went to Poland to buy a Phone with pre installed #Firefox OS on. The Phone was a Alcatel One, so very shitty. Two years later I installed Firefox OS on my Nexus 5 instead.
It was a very good concept, but sadly rolled out on too shitty hardware so it never caught on.
Imo that’s what caused Firefox to lose market share to Chrome. They focused too much on Firefox OS and deprioritized browser development. In one example, it took them a long time to implement FIDO when it was already functional in Chrome.