What else would they be running? VMWare abstracts the machine from the hardware in a very literal sense, with live migrations between hosts, etc. so you can work with your boxen without interrupting any customer services.

If that capability suddenly costs 10x-100x more due to licensing, the margins stop being there - you'd need to rise prices above whatever aws/azure/gcp is doing and that's obviously not going to fly with customers. Shutting down is the only reasonable choice; unreasonable choices like develop your own vmware alternative or use an existing open source solution don't make sense for anything above micro and below hyperscale. The mid-market has been rugged, gutted and driven over by a Buick.