When most people talk about VMs these days they mean something similar to the Popek and Goldberg definition, which wouldn’t be achieved on x86 until a decade later.
I don't think P&G implies that the VM needs to run with exactly the same capabilities and characteristics as the host architecture. If that were true, then probably a large amount of modern virtualized machine are suddenly not P&G anymore, just because some obscure CPU (or other) feature might not be available in the VM, which is not a meaningful distinction.