Oracle and VMware per-socket licensing is one of the main reasons server-class CPUs have gazillions of cores. A vSphere licence+support for a single machine can easily run into 5 figures.

That's still a common billing model- how Red Hat bills for openshift for instance.

It's a simple and pretty good proxy for usage

Pretty sure they still do for some software they sell ;)

Maybe thats why POWER chips have so many SMT threads per core