Yeah, as you say, this is where we part company.

But for what it’s worth, this is also where you part company with the entirety of human history. Despite our flaws, we live in the richest, safest, smartest, healthiest, fairest world that has ever existed. We have created this world, not because human nature has changed, but because smart, decent people on the political Left and Right found better ways of managing humanity’s flaws and living together.

Of course, there's no way to build a perfect world. I think only the most unhinged moron believes that there is. There is something inherently unsolvable about the human condition. But all you're doing is making perfect the enemy of good. There is nothing insightful or original about being that person at any given point in history saying "Stop wasting your time! This is the best society is ever going to get."

The people who say this have always existed and they are wrong literally every single time. And usually they're only saying it because the system works okay for them and they don't care that it doesn't work for other people. It's not rationality, it's just selfishness.