If you ban legacy, then you lose needed donations. If you lose donations, then costs go up for everyone else. There is a net benefit for everyone when there are academically challenged wealthy children. Just keep standardized testing to prevent mass arbitrary admissions that will inevitably become racist.
https://priceonomics.com/do-elite-colleges-discriminate-agai...
It’s happened in the past to Jewish people and it’s now happening with Asians. It’s routine to hear admissions officers say that Asians are boring.
If the end goal is to eliminate any sign of a meritocracy, they are well on their way to achieving it.