That's how it's supposed to work, yes. And any software that does that should probably work fine on Apple Silicon, by falling back to the non-AVX path under emu

That's how it's supposed to work, yes. And any software that does that should probably work fine on Apple Silicon, by falling back to the non-AVX path under emulation. I've seen some poorly behaved Mac software which used AVX instructions without testing for availability. It crashes if run on some older Macs, and it won't work at all on Apple Silicon.