Does Harvard not take this into account and adjust their courses to actually be of a rigor that challenges students?
If 60% of people are getting a "full A" are they all truly equally capable? Clearly not, right?
Especially for less structured things like essays. Imagine reading your friends paper and finding issues with it that are left wholly unaddressed and then finding out they got an A just like you.
Consider AP. Sure, everyone taking an AP test is more academically engaged than those who don't, but why would that ever indicate that 60% of AP testers get 5s? In fact, looking at last years results, most tests seem to have populations centered around 3, with only a few (or maybe just the CompSci one) having populations where 5 is the most common.
The whole scale's wonky anyway. My sister worked extremely hard to be first in her class, and I made almost no effort to drop out and get my GED before my class graduated because my state didn't allow early graduation. We both know which of us is more intelligent and which is the harder worker, but our grades don't tell the story.
Perhaps we should look into why they received A without actually actually crossing the required threshold, rather than imposing arbitrary percentage limits. From the other side, if they do all demonstrate "extraordinary distinction", why should 29% of them suffer and not receive an A? I don't think the problem here is the number of students receiving A's, but instead what an A actually means.