For clarity, in this context I think @
vetrom was talking about emulation, not a virtual machine. A virtual machine makes use of the native instruction set (relying on the hardware) to create a machine within a machine and naturally can only create virtual machines of identical hardware capabilities (or a subset thereof). Emulation does all of that in software and could emulate even a completely different architecture.
Though to get fast emulation, you can re-use techniques from virtual machines (and vice versa).
Btw, emulation is how you can, in principle, run Linux on an 80286. (Normally you'd need a 80386 at least to get memory protection.)
Of course, Linux on the 80286 is gonna be even slower than Linux in your browser. (https://bellard.org/jslinux/)
Using the emulation idea you can go almost arbitrarily primitive. But the 286 is a nice target, because it was a sometimes requested feature in Linux's past.
