Yep, skilled people have options. When you are treating them as circus animals that constantly need to prove that they are worth the cage they will be put in and the food they will be fed, they just leave the circus.

Smart professional people desire non-hostile space where they can build a life. When a Russian scientist or Iranian doctor left their countries for London or Paris, they were't calculating for a net income increase, they were running away from an environment that didn't show a promise to allow them realize themselves. Lot's of white collar people are paid well below what they will make if they learn a JS library or do construction work because of their desire to fulfill themselves in a peaceful life and be respected. It is kind of similar to game devs being paid very little in respect to the complexity of the programming they do. If you break that magic, they aren't going to stay.