> A well-known limitation is that Apple only allows two macOS VMs per physical Mac. It can be a Mac Pro with 24 cores and 192 GB memory, yet it is limited to running only two guest VMs. This limitation leaks into our product offering: we can only slice Mac resources in two halves. So we run instances with 6 or 12 cores on 14-core Mac Minis and 8/16-core instances on 18-core MacBooks (we reserve a couple cores for management overhead).

I don't know about selling, but Apple permits up to 2 virtualized Macs to run on a Mac. If they are circumventing this limit that would be an issue, but it doesn't sound like they are.

To be fair, it was against Microsoft's EULA to sell the OEM version of Windows to individuals who built a computer from parts.

Nobody cared.