I think the main reason is that they want to ensure the best students can attend, regardless of their current income. Successful alumni are more likely to contribute back to the university in the future.
I graduated from Vandy within the last decade and can attest that their financial aid program has been great for a while. There’s no way we could have afforded it without their assistance and I was able to graduate with very minimal debt that I easily paid off.
POV you’re Eustace from Courage the Cowardly Dog