Note that most publics feel that it’s their mandate to serve all communities in their state, and that isn’t going to change regardless of whether profs are admitting or not. They will not have full control over admissions.
Likewise, many schools would still have to satisfy institutional needs. Privates need to keep alums happy. Sports programs need their athletes, etc.
The US is not Europe or Russia. If your prof friend prefers the Russian admission philosophy, they could always teach in Russia instead.