Harvard doesn't need anybody's money, but they sure aren't going to use endowment money to make things free. They want your money, regardless of whether or not they need it, whether it's a huge status-signaling donation or a drop in the ocean semester's worth of tuition. They absolutely are trying to optimize how to get that money, now and in the future.
I also think you underestimate how much big scions of generational wealth compete for status symbols like Harvard degrees. Once things become decoupled from money, that type of status signaling only increases in importance, lending legitimacy to the children of foreign rulers and diplomats, acting as a currency to normalize political relations with western countries or between corporations with vastly different political party affiliations.
Harvard sells status, and absolutely is looking at how to monetize that. If offering a pittance of tuition relief to underrepresented groups helps maintain their entrenched brand status, they'll do it because of the long term effect on their ability to monetize reputation, not in spite of.
It also reminds me of how Harvard absolutely hounds graduates for donations, despite utterly not needing them by comparison to what Harvard Management Corporation does. Mike Reiss (Simpsons writer and Harvard alum) skewered this in [0], saying among other things,
> "Harvard is like a bum who starts bugging you for spare change on the bus. And then follows you around for the rest of your life. Oh, and that bum already has $40 billion in the bank."
[0]: < https://features.thecrimson.com/2014/fm-comedy-issue/article... >
I thought Harvard did make it essentially free to attend if your parents have a middle class income.
20% of undergrads going tuition-free is just part of Harvard’s marketing budget. It’s not philanthropy, just the cost of doing business if your business is elite status signaling.