[Symmetry]

Plausibly we're headed for a world where feature size decreases stall out but manufacturing improvements continue to lower the price of transistors over time. In a world like that throwing in a few x86 cores even if the dominant ISA shifts might be worth it from a backwards compatibility standpoint even if other ISA become dominant.

There's lots of complications to address there (strict x86 memory ordering versus loose ARM ordering, for instance) but I expect they're solvable.

[tracker1]

IIRC, AMD's model for chiplets could already combine x86 and ARM as an example, not sure if any such beasts are in existence, but should be possible.

[Symmetry]

Yeah, I'm actually thinking something like a socket integrator buying an 8 core chiplet from AMD or Intel to connect via CXL or whatever to the ARM/RISC-V/GPU/Tensor cores in the other chiplets from different manufacturers.