I don't think it's that clearcut. There's a cultural DNA. Folks behave a certain way then when they grow up their children behave the same because that's how they saw at home. Principles and basic morals are not enforced at home etc.
I'm basically arguing that nature is less important than nurture, even if nature might indeed be worse than we think.
People inhabiting the Russian empire weren't all that bad. But there were multiple stages of descent into the atrocious society I remember from the late 90s. It also didn't go in a straight line. The 70s in the Soviet Union are remembered as the time of a "standstill" because for the average citizen, the life was mostly palatable, the living conditions gradually improved and people were genuinely nicer (than, say, during and right after the war, or in the early days after Stalin's death). They didn't know that the state, as a whole, was living on borrowed time sliding deeper into a credit hole.
This is also why the Russian version of "boomers" wants to go back to the Soviet times so much: they remember the 70s and how much nicer everyone was.
Oh, and since we are here already, I'm going to mention my favorite quote from Dostoyevsky (from memory, maybe not 100% correct):
> Poverty isn't a vice, but destitution, kind sir, destitution is a vice.
This was spoken by Marmeladov, a former government bureaucrat who started drinking after being laid off and to make ends meet took to prostituting his daughter, Sonya, the love interest of the protagonist, Raskolnikov. His idea was to say that there's a threshold in poverty, where a person breaks and succumbs to the vice being no longer able to afford to behave decently. Obviously, using himself as an example.
Poverty was also the motivation for Raskolnikov to kill the pawn shop owner, however, he didn't think about explaining his behavior in this way. I'm not sure Dostoyevsky himself would side with Marmeladov's explanation of the nature of vice, but he definitely considered it :)
I keep explaining to boomer members of my family that things were not good during the communists. It just seems bad now because of the news and social media. They are better off than 90% of the people in their country, but they don't perceive it.
Anyway, I think people who have been "civilized" for a long time would also take a long time to turn uncivilized. Which might mean never, since they would also do their best (as a tribe) to get out of poverty quickly.