My experience with open source linux phones is that they can never make basic decisions like which package manager or ui framework to target, so you end up with five completely distinct base operating systems. Some can make calls, some can receive sms and some can suspend resume. None can do all three. If they’d picked one standard approach they could have all those things with 10% the effort I’ve seen go into those ecosystems.

I don’t think there’s anything particularly hard about producing an open source linux phone with modern hardware and a supported base operating system that is competitive with a typical dumb phone.

However, none of the companies that have tried to make an open source phone are product focused enough to build such a thing.