Even if Zenimax is claiming to own John Carmack's work, under what supposition do they make the claim that they own the knowledge in his head. Assuming he did not break a non-comptet e clause, how is it that they can claim that because he gained knowledge of how VR systems work, while working for them that they own that knowledge in his head?

I understand typical IP policies, that they definitely own any code he wrote and are capable of patenting ideas generated by him in that work. This seems to step beyond that however (if indeed he used no code from id software at oculus).

Perhaps I am being naive, but as a software developer, this seems to me that they are attempting to set a dangerously non-competitive precedent. Under this logic, because I learned how to do advanced SQL queries over an internship (assuming a similar IP policy), I could never write SQL for any other company. That is a much simplified analogy and is likely missing some specifics, but I would honestly like to know the basis for this type of lawsuit.