But they can't take the oil wells and other natural resources with them.

That's the problem of countries with many natural resources -- they can afford to get rid of their best people.

That would not necessarily concern Putin too much, as the ones with brains almost by definition would not be too happy with him.

I know you are getting a zinger in, but yesterday's HN darling might be evidence against that:

Many scientists protested, but Elbakyan didn’t understand the outrage. As far as she was concerned, Dynasty — particularly through its funding of the LMF — had spread “propaganda against Putin and the Russian authorities.” She describes Zimin’s work through Dynasty, and the organization itself, as “anti-communist,” though she’s vague about how. Elbakyan says the foundation and Sci-Hub are “ideologically opposed,” and contends that Dynasty is somehow Sci-Hub’s capitalistic foil.

Actually it's exactly evidence for that -- anyone who considers "anti-communist" to be a bad thing, especially so in the ex-USSR, lacks both brains and even a single shred of human decency.

Not that I thought much of her before anyway.