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.
There was no change in trade regulations until 2021. The UK government insisted all along that they would get "the best of both worlds" and "no friction". While there was a reduction in demand from the EU side, acknowledged by most pre-established businesses, if you started in 2017 you wouldn't have seen it.
Kimi was a mug for believing lies from the UK government, or hoping/betting that things wouldn't get as bad as they did. A softer, saner agreement achieving EEA-like status would have been fine for him, after all. But nope, we got our hard brexit...
focus on lower end devices and that's not inherently stupid.
It is. Phones are an aspirational market, it's the top end that sets market trends. It's been the case since 2007 at the very least, and arguably well before that. Focusing on the low end was a huge mistake from Mozilla leadership, and it's sad that nobody seems to have paid a price for it (beyond the FFOS team, which was eventually disbanded). FFOS almost killed Mozilla.
Jerboa is pretty bad in many, many ways; at one point it almost killed Lemmy for me. Sync is at least polished and robust. I've not seen ads yet but I wouldn't be opposed to paying something for a decent client - I used to pay for Narwhal too.