The main issue will be application support.

Linux running on the desktop in 2025 is helped immensely by everything being web based. So long as you have a browser you are fine for a lot of general computing.

The phone space is ruled by apps. The phone makers and the companies developing apps prefer it this way.

Getting a banking app, or Uber or Facebook Messenger to work on a Linux phone is going to be a massive pain in the ass (ignoring the rest of the OS which is definitely not even close to useable for the general public).

I would love a Linux phone but we are so far away.