No we don't, because it would be UNIX command line and X11 on our phones, as proven by multiple attempts to GNU/Linux phones since OpenMoko.
For all their flaws, iOS, Android, ChromeOS, and the gone Blackberry, Windows Phone, Symbian, actually rethought the whole programming stack, using modern programming languages, and UI/UX.
And security, don't forget that. Proper app isolation on Linux is still very tricky, with many competing approaches in Apparmor/Selinux/Snap/Flatpak/Docker, all complicated to set up and use. The consequence is that in practice a 2048 game has unlimited access to the files in my /home folder.
On the other hand, Android has a very solid permission and isolation system. This is why I don't want GNU/Linux on my phone; I would rather have a proper FOSS Android.
The Android approach is among the most "complicated to set up and use" (since it's based on SELinux under the hood) but the OEM does that for you. There's no reason why Linux distros couldn't do the same thing using Flatpak and/or bubblewrap. (Plus AppArmor for extra hardening where sensible.)
For all their flaws, iOS, Android, ChromeOS, and the gone Blackberry, Windows Phone, Symbian, actually rethought the whole programming stack, using modern programming languages, and UI/UX.