Assuming "upset" is referring to simply the seeds, then this isn't stating Cinderellas are dead - this is stating the gap between the elite programs and the field is growing. Kentucky just got beat by 19 today and Iowa State's best player (arguably) didn't even play.
It's not a NIL problem - it's a Transfer Portal problem. That is the #1 issue that needs resolved in college athletics. Not only does there need to be some sort of limitation on movement, but commitments need to be minimum 2 years contractually. Also, teams need compensated for losing talent, especially mid majors.