Except the U.S. right now is nothing like what the USSR was under the Soviets, at least not for people who are in the U.S. via proper and lawful immigration protocols. The bent towards Christian nationalism may covert the US into an unviable USSR-like environment for a majority of its population, including whites and Christians. But I don’t think that scenario is likely given the range of leadership available to the U.S. I guess it depends on how the next two years unfold, maybe I’ll stand corrected.

Regarding brain drains, why is it so bad if the best and most productive of another country stay in their home states, or go else where? The fact is that there are a lot of nations which experience relatively low rates of immigration, but are at the forefront of science and tech, such as China or Japan or Singapore. Maybe brain drains are not the main concern here, if anything the idea is a distraction.