Yes they do. It's called "another Mac". And I'm not even being snarky here: I legitimately think someone at Apple thought this through and said "yeah if they need more than 2 VMs running at the same time, there are probably multiple users and they can each get their own Mac".

The option is you have to buy another machine. There are mac ec2 instances and several mac cloud hosts that all would abuse this if they could, instead to stay compliant they buy more machines.