Because capitalist Russia is pretty shit. The only thing it's good for is opposing the US hegemony, but even then it's still pretty cringe with it's capitalist oligarchy.
Compare modern day Russia with shit like the Soviets sending the first women to space. Seems like they were pretty progressive for the time compared to now?
How the mighty have fallen. You hate to see it.
That's just a constant function of brain drain, though. One of the benefits for the imperialist countries that receive said emigrants is that it's much harder for a country whose educated professionals have left it to progress past the conditions that cause the exodus, it's a self perpetuating problem.