AFAICT, the ivies don't have a problem with filling their graduating class. I believe a place like Harvard even considering the top 10% of students would increase the applicant pool. I'm reciting these numbers from memory, but apparently the size of the incoming class at Harvard is roughly 2,000 students, but there are ~5,000 applicants that scored 95th percentile of the SAT. (Edit: This source [3] says there are 22,000 students who scored in the top 1% percentile; Harvard could likely admit every perfect scorer if it pleased).
While I believe there is belief that Harvard is accepting C-students over asians A+ students I think the reality is much closer; they are rejecting students with perfect scores and accepting students who scored in the 98th percentile.
The real problem is the size of the undergrad class for these select elite schools have remained the same (The harvard class size of 1992 was 2,200[1] compared to 1,954 today[2]), while the US population has grown almost 30% in the same time frame. You have more and more qualifying students fighting for the same number of spots and an organization that is more than happy to split imaginary hairs to keep the class size the same.
[1] https://www.thecrimson.com/column/a-new-day-at-harvard/artic...
[2]https://www.thecrimson.com/article/2022/4/1/admissions-class...
[3] https://go.collegewise.com/how-many-people-get-a-perfect-sat...