There were these ancient Ukranian mega cities 6-4k years ago that stood for thousands of years. They had gardens, and what appeared to be a complex social life. Notably, they had no walls, meaning there was nothing to protect themselves from. Peace.
So yeah, there sounds a lot better. No walls to stop friends from coming, or you from leaving if you happen to not like it.
Just because we lack imagination doesn't mean a better world can't exist and didn't exist somewhere in the past.
Ignoring whether or not that actually existed, that's as useful as saying "I'd rather be a lottery winner or a king".
The point is that the average person is better off today than they were any time in the past by many metrics, e.g. life expectancy, quality of life or access to healthcare.
Nobody said the status quo doesn't need to be changed, only that we should appreciate the pax americana despite its faults.
