Unfortunately other than the hacker niche that's on this forum you won't get the average consumer using these devices/OSes and therefore you won't get the apps that attract people to use the devices in the first place.
So, while there will be some effort required to make gui programs work, libhandy supposedly makes this pretty easy. It's an order of magnitude less effort than porting an app from a different platform. Not to mention that everything CLI should Just Work -- this is not relevant to most mainstream users, but it's very relevant to the developer story; I think it's likely that FLOSS developers will start targeting these phones as soon as they become usable enough to developers. Personally, I'm planning to get a Librem 5 as soon as they're off backorder and there are reviews from non-affiliated parties (the latter might be now; I check every couple months and it's been about that long since I checked last).
If anything, it proves the point that GNU/Linux doesn't sell phones to make a sustainable business out of it.
The need is not going away anytime soon. I generally like what Apple and Google have done for the mobile phone market, but it’s time for folks to take back some control of their devices which the execs will likely not agree to.
The radios are too locked down and the software too. Despite good intentions, I’m concerned this gatekeeping could become corrupted/corrupting in the future.
If you support the rough and tumble world of open source and systems, you’ll plant a seed that a future generation can grow and compete with gatekeepers. This may reduce the corrupting forces from the gatekeepers. They could point to open systems and say, “Look government, your plan won’t work because 3% use an unrestricted phone, and more will follow if you force us to do X to everyone’s phone.”
They've got some funding from Google[3] as well.
[1]: https://www.kaiostech.com/
[2]: https://www.financialexpress.com/industry/technology/relianc...
[3]: https://www.theverge.com/2018/6/28/17513036/google-kaios-inv...