I think the groundswell of support from the ultra-low-end is the only thing that I think can help it overcome ARM's headstart. It will not be abandoned by embedded users because of the lack of the ARM licensing fee, so it will always have some major users and thus some funding to keep supporting the community at the low-end and not letting the tooling bitrot and disappear. It's taught in universities as well. That is fertiliser, still not sure if it will bloom.

For better or for worse (for them I mean), ARM seems to be selling their licenses at fairly low prices, so that they don't need to be incredibly much better than RISC-V to stay attractive. ARM just doesn't feel like the evil empire of embedded computing that everyone wants to beat.