NXP is still making PowerPC proper for lighter weight applications – the T2080 is currently being used in a laptop project over in Italy. Quad 1.8, so not the fastest, but quick enough for full-speed YouTube and much faster than the MNT laptop.
Then there’s the T4240, which is 12-core…
I wouldn’t call POWER9 overly expenive – a typical build should cost somewhere around $2,800-3,000, which seems to be reasonable to me compared to PC builds on /r/buildapc.