More than anything, the problem is apps. I installed Ubuntu Touch on an old device I had lying around (after replacing the battery to bring it back to life), and I ended up liking it more than my daily driver. It worked, the interface was snappy (no pun intended), and there's a lot of solid design choices. I found myself trying to navigate with gestures on my android phone after.

However, I could not talk to my friends, who unfortunately use WhatsApp. I could not install my banking app. There's a bunch of small thorns in the side that makes changing difficult for most users - kind of like in the early days of desktop Linux.

As in the early days of desktop Linux, the solution might lie in a compatibility layer (like WINE). Android emulation within at least Ubuntu Touch has gotten quite good, I believe. Unfortunately my device is too old to support it.

Those interested should also check out Postmarket OS.

GNOME, a major desktop environment, is also moving towards all apps being designed for all types of devices. But as long as people can't use their banks, switching is hard.