It’s completely untrue that Harvard could get as many perfect scores as they want. Harvard has a class of 600, and they are contemporaneous (actually slightly below, lately) with Yale and Stanford. If 160,000 people take the LSAT, as happened last year, there would be only 160 people with marks over 178. Take into account that lower tier schools give nice scholarships for good numbers, while the top 3 only give need-based aid, and you see why high numbers are in such high demand.
Yale, on the other hand, has a class of around 180, and indeed, they are less beholden to numbers.
Popa, “Law schools are mainly interested in putting out a quality graduate,” is not really true. They are mainly interested in maintaining their US News ranking. Former deans openly admit that admissions falls back onto the numbers because that’s the best way they can rise in the rankings.