[JockoManning]

I don’t know of such a situation where a professorship requires a license.

[philman_36]

I don’t know of such a situation where a professorship requires a license.
It isn't about teaching, it's about certification.

Look at it this way. A person may know how to wire a house, but only a certified, competent, licensed electrician can actually do the job.
You grok?