I once interned on IBM's PowerPC JVM team 10 years ago. Most of our customers were enterprise customers running monolith applications e.g. governments and banks. IIRC the main advantage of PowerPC was a much wider bus resulting in higher memory bandwidth than x86. I'm not sure if that's still the case today but I doubt anyone in those orgs want to take the risk of switching to an entirely different architecture and risk losing millions of dollars if something goes wrong.

Don't fix what's not broken