Android runs toybox (or at least used to), which implements many of the GNU tools. But I think the complaint is that much of the userland to have a useful phone experience is proprietary.
If you could install all the GNU tools into AOSP Linux (probably not that hard), you still don't have a useful phone.
It's not even the desktop environment (think GNOME/KDE/etc.), as there is a good enough version in AOSP.
All it takes is one good phone application that uses the underlying devices.
Also as a reminder, WebOS is also Linux and the Palm Pre phones were excellent phones (with a somewhat limited app support - they were a bit ahead of time with JavaScript and applications written on it)
Why is the title “Is there hope for linux on smartphones?”?
If it said “Is there hope for GNU on smartphones?” the answer would be a resounding no, because the community is fractured and politicized to the degree the products are uncompetitive. Pinephone is an example. Then there was the Ubuntu effort.
Android, being partly closed as the GPL2 allows for, is proof that Linux can be highly successful without the GNU crowd. And perhaps they should stop taking credit for software they didn’t write. They made the license.
For all the complaining, the free software community hasn’t designed from the ground up and released one single production class handset alternative at a time when the culture consumes in the billions. That’s says a lot. The infighting and utopian idealistic virtue signaling is in sharp contrast to the reality of the platforms the GNU crowd has built.
If you could install all the GNU tools into AOSP Linux (probably not that hard), you still don't have a useful phone.
It's not even the desktop environment (think GNOME/KDE/etc.), as there is a good enough version in AOSP.