There have been way better options since almost the beginning in terms of design/arch/boarddesign than RPi with their weird VCore monster. Nobody has displaced them in like a decade. I doubt a change of architecture is the final push needed

I can buy a RISC-V board, I can't buy a Raspberry PI.

That is actually starting to change, and per Eben Upton’s very recent interview with Jeff Geerling, should be approaching back to normal for hobbyists in coming months.

I’ve checked rpilocator a few times this week to find 4Bs available every single time. Not tons and not everywhere, but they’re starting to have availability again.

ISA will not matter. Features and how well it works out of the box will.

rPi have hundreds of competitors and they still sell by far the most amount of SBCs, because "it just works" with many things supporting it out of the box