You speak as if 50 years is a significant period of time. Tribalism, violence, and distrust are still very real forces in the world and there is nothing "simple" about granting historically unprecedented powers to a central authority.
When you start looking more than 50 years into the past you need to realize that this was a time when people thought blacks were lesser people than whites, women couldn't vote, many people were illiterate, people didn't have access to information, and maybe most importantly people were much much poorer (just look at the GDP). Now a days people for the most part live comfortable lives, and what we think of as "hard times" now is not the same as before (where it would often mean starvation for a large segment of the population) So to think history will repeat itself seems to me very simplistic.