That’s not a comparable scenario. Your scenario doesn’t exclude participants, but the change reduces their win potential. The Stanford/SC/etc fraud doesn’t change the process for most students. They were still evaluated and admitted or not based on the merits of their applications (I’ve seen no evidence to the contrary). Because of the fraud, there are obviously a small number at each campus whose potential spots were taken by “unqualified” frauds.
But, the very fact that they weren’t admitted shows that they were on the cusp anyway, so proving that they were excluded only because of the fraud will be a tall order. Even more difficult at the private schools.
Here’s a better comparison. A new club or restaurant opens to huge hype. Everyone wants to go. Opening night, the line stretches down the block. People wait for hours to get past the doorman. Limo drives up, out steps the high roller in a suit and his gorgeous daughter. They walk to the doorman, daddy puts a couple folded hundreds in the doorman’s hand, and his daughter goes into the club. No line, no waiting. Daddy goes back to limo, while the regular folks stand on the sidewalk and wish they had a couple extra hundreds. But nobody sues. Nobody thinks it’s really fair, but they really haven’t lost anything but time.
Application fees don’t entitle you to admission. They really don’t even entitle you to a particular process. They’re a processing fee that say you’ll be reviewed and considered. You might get passed over for someone with a better GPA, better test scores, or both. Or for someone with more community service and involvement. Or for someone whose intended major is in a program of emphasis. Or for someone who brings greater diversity to campus. Or - particularly at private schools - someone who brings a little bragging rights, like celebrity kids. There are a lot of factors evaluated in admissions, and while grades and test scores are among them, they aren’t necessarily decisive, especially when down to evaluating candidates that are close to the cut line.
Even at state schools, if two kids are equal in every way, except that one has a parent who’s a donor...guess which one is getting in?