I think Rosetta is mostly about userspace, and a Hypervisor is definitely not something that sticks to that - modern VMs run on the bare metal thanks to CPU acc

I think Rosetta is mostly about userspace, and a Hypervisor is definitely not something that sticks to that - modern VMs run on the bare metal thanks to CPU acceleration and dedicated instructions (i.e. VT-x and AMD-V). Getting an app to run on a foreign architecture it's different than emulating a whole machine in order to get an unmodified OS kernel to run. You can do it this very day with QEMU, yesterday I tried just for fun to boot Windows XP on my Raspberry Pi 4 (it boots but it's horrendously slow, if you're interested). Maybe with time and effort, an emulator can get a satisfactory level of speed (probably never enough to run Windows games on emulated Windows though, but who knows).