Anybody who formalizes their "homebrew KVM platform" into a marketable hypervisor product is going to make a lot of money I suspect. Every IT department I know is scrambling to replace their VMWare stack ASAP, including very large ones.
this doesn't sound right, both serve different purposes
At least some of the big ones seem to just pay up. Probably because they / their MSP / their relationship with their MSP is so dysfunctional that they know migrating is a pipe dream.
Disclosure: I also work in Red Hat's virtualization team, but not on converting gusts from VMware to KVM.