Hello RestlessDevil
In my opinion - snaps are primarily for IOT and servers. Flatpaks are only for the desktop. At the end of the day it will be the developers who decide. If developers package their software as flatpaks, and not as snaps, Canonical would have to re-package desktop software as snaps themselves. I am not sure they would choose to do that. Perhaps my perception of the situation is wrong. Time will tell. 
Wimpy has built the basis for flatpak support into 22.04. I suppose the Ubuntu-flavours have more freedom of choice.