Over half of all students accepted to Harvard already have test scores in the top 2%

Yes but then you invite the idea that the “meritocracy” is biased because only rich kids have the opportunity to study and achieve the top 2 percentile scores needed for admittance. This argument has been used against Texas schools, specifically A&M and UT, who currently work with a “Top 10%” rule where the top 10% of any class in state is automatically admitted to any state school.

Note that I am not expressing any opinion about any of this, merely pointing out the counter argument.

> I'd love to see Harvard set aside 75% of their spots for a lottery of students who meet an insanely high threshold (98% percentile in the SAT, for example

Insanely high threshold? That's... a very low bar. https://www.statista.com/statistics/195908/number-of-births-... (no idea how good this source is) shows roughly 4 million births a year. A 98th percentile cutoff would admit 80,000 kids per year to Harvard. By contrast, according to https://college.harvard.edu/admissions/admissions-statistics (hopefully a strong source), the class of 2021 admitted 2037 people of which 1687 enrolled.

You would hope that 100% of Harvard admits would have 98th percentile (or, really, better) scores, but they don't.