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.
But they didn't manage to - nobody will, not writing an OS from scratch. To support that level of development you need high per-device margins that only high-end devices can command. The low-end is restricted to low-margin new devices and secondhand high-end models - because, despite your preconceptions, high-quality models can work for a decade when not abused. The poor Nigerian will buy a secondhand flagship today and, if they get wealthier, a new one tomorrow; they know the market as much as anyone and will not buy something that simply makes them look poor.
The view that the developing markets will eat shit simply because it's cheap, is an out-of-touch colonial mindset that dooms a lot of companies.