This suggests that everyone going to college is doing well. That isn't the case. There are people who have master's degrees, but are earning $15/hour. I agree

This suggests that everyone going to college is doing well. That isn't the case. There are people who have master's degrees, but are earning $15/hour. I agree with your point that populations can change over time. Fifty years ago, many people didn't get degrees and made good money. Today, people without degrees (and some with) don't make good money. So instead of trying to segment in groups (the college educated vs. everyone else), let's just look at everyone. This removes the concern of our shifting populations. One metric to look at is median income. Adjusted for inflation, it hasn't budged much in decades. In the past 42 years, it's increased about 32 percent. https://fred.stlouisfed.org/series/MEPAINUSA672N https://fred.stlouisfed.org/series/MEPAINUSA672N