I think it's more simply a "Cui Bono?" thing.
Most professors are academics.
Most academics get their funding from the State.
Mises, Rothbard, and Hayek attack the State.
The State doesn't fund research and academics that would attack its own interest.
Academics in turn do not usually mention Mises, Rothbard, and Hayek.
In turn, most professors and classes do not mention Mises, Rothbard, and Hayek.