Harvard’s endowment covers roughly a third of yearly operating expenses. The rest comes from tuition (21%), current gifts (9%), research (17%) and other (17%). Even with this, last year Harvard ended the year with an operating surplus of $400M.
So what @niceunparticularman wrote makes a lot of sense. It took Harvard 300+ years to accumulate an endowment of $50+ Billion. They are simply not going to discard legacy, at least not in the near future. Once the endowment covers more than half of operating expenses then it might make more sense. At least then they wouldn’t need to worry about tuition dollars.
Harvard’s dominance in the rankings is mainly due to its fat wallet. I don’t see them doing anything to sacrifice that in the near term. Even if all of their current donors stopped giving money, it would amount to a relatively small amount (~9% of operating expenses). But in the longer term it would make them less competitive to keep up with everyone else.