Earlier quoted context omitted.
The point of the report is that SAT scores are less correlated with socioeconomic status than other metrics used by admissions like GPA, high school reputation, extracurriculars, essay content, etc. They're still correlated. One of the interesting findings of social science research is that a lot of different metrics like IQ (itself a correlation between different subtest performances), GPA, parental income, child's…
A Harvard, Princeton, and Yale alumni survey found three-quarters live in zip codes that rank in the top 20 percent by income and education. Half live in the top 5 percent of zip codes. So their efforts didn't work.
If I flip your numbers around, it actually sounds pretty good: a full quarter of the alumni come from the bottom 80% of zip codes!