To be fair, a lot of software already supports POWER right now, including the Linux kernel, compiler toolchains, the OpenJDK, various database engines, and so on. Don't forget that a lot of embedded devices used PowerPC in the past and it was easy to get PowerPC based hardware like e.g. old Mac computers or game consoles. Today you can get large POWER based servers which compete with big multisocket x86 servers.

I think the main problem of POWER today is that you can't get a "Raspi sized" development board, while you can easily get all kinds of ARM based SBCs as well as various RISC-V based SBCs. The smallest POWER system you can get right now is iirc a workstation from Raptor which essentially competes with Xeon workstations, if you don't want to play around with soft cores on FPGAs.

But where the rubber hits the road seems to be in niche stuff like accelerators (which is indeed a great application for RISC-V) and low power embedded stuff.

Other countries (like Russia, and China's MIPs thing) have pursued novel architectures for higher power general purpose computing, but its mostly for government use I think. China pulling off a societal transition to RISC-V would be quite a coup.