Graduating from college is correlated with better life outcomes in a lot of areas, including income, health[1], and life expectancy[2][3].
The causal effect of college graduation on those aspects of life varies, but the correlation is so strong that it makes sense to use it as a proxy for "better".
Just if wealth is correlated with graduation, and graduation is correlated with success, doesn't mean that wealth is correlated with success.
If anything, the article could be interpreted to apply the opposite - those skilled poor people that do graduate have climbed so high so fast compared to unskilled rich graduates that they're very likely to climb even farther further in life.
The causal effect of college graduation on those aspects of life varies, but the correlation is so strong that it makes sense to use it as a proxy for "better".
[1]: https://www.luminafoundation.org/files/resources/its-not-jus... [2]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4435622/ [3]: https://www.mpg.de/10795685/longevity-education