> If consoles did it, it would most likely mean a break in backwards compatibility or a lot of investment in emulation.

Consoles tend to break compatibility every like couple of generations anyway. The PS5 is only compatible with PS4, for example, because the PS3 used the PowerPC-based Cell. Also, Nintendo has been using ARM since like, the Gameboy Advance (Fun fact is that in handhelds nintendo tended to use the previous generation's CPU as a sound chip, and would use it when running previous generation carts) (Nintendo home consoles before the switch used PowerPC. The Nintendo 64 used MIPS)

I agree with you on the custom PC market, but that has to be pretty small compared to consoles.