I think today, there is much more variance compared to 50-70 years ago. Those who have high intelligence and 'drive' have much more opportunity for advancement and to become wealthy ,compared to smart people of 70 years ago. But, opportunities for people who are not so smart may be more limited. Nowadays, you got plenty of smart people making money with high-paying white collar professional jobs, right out of college, whereas 50-70 years ago, such jobs didn't really exist and pay was lower relative to inflation and even after accounting for student loan debt. There was no equivalent of $400k tech job in the 70s. There were plenty of manufacturing jobs, but the pay even then was not that lucrative. Same for being a doctor, a lawyer, or a consultant. Those jobs payed more, relatively speaking, but not like we see today.