As a point of comparison, Microsoft ships its OS across a variety of manufacturers and largely keeps it maintained across them (give or take some exceptions like enterprise environments & the like).
Even unlocked Android phones purchased independently of carriers have inconsistent lengths of support, so it doesn’t seem to be entirely a result of carriers, so…What happened here?
That sentence is completely correct from my point of view and has nothing to do with Foss. That’s an issue for Windows as well as Linux and Android. I think the difference is that that for the former two driver developers just take the extra effort to support hardware long term. So I think you’re right that a little rewording would help.