I think you're underselling it a bit. It's supported on RHEL, SUSE, Fedora, Debian, Ubuntu, several more niche distros besides, but aren't those the dominant OS

I think you're underselling it a bit. It's supported on RHEL, SUSE, Fedora, Debian, Ubuntu, several more niche distros besides, but aren't those the dominant OSes outside Windows (for servers/workstations)? Unless I'm misinterpreting the meaning of "outliers". And support goes out pretty far. Just to rattle some examples of public "support" for power8/9, Anaconda lists power9 binaries under x86 for their installer (no mention of ARM), PyPy has Power support, V8 has Power support (the basis for Power ports of Chromium w/JIT'd javascript), nvidia has Power drivers/CUDA runtimes on their main download portal. I'm not trying to paint it as largely supported or even a great platform, but I think it might now be better supported than it ever has been. It's little-endian now, software compatibility is almost 100% outside of JIT'd things (and many JIT'd things have Power ports). If/when it fails or fades away, it'll be because it wasn't good enough to displace the alternatives, rather than because no one supported it or it was too difficult to use/support.