It's difficult to say for certain that the Ivies are actually that high in terms of academic quality. There's a history of people literally tweaking evaluation and ranking criteria until they get the Ivies to come out at the top. For example, US New and World Report got rid of a statistician whose algorithm didn't put the Ivies at the top of their rankings, and replaced with someone who would "fix" that:

https://washingtonmonthly.com/2000/09/01/playing-with-number...