The university will argue that a well-rounded student body improves the experience for everybody. IE, a college that's 100% "nerds" won't be as good as college that's 80% "nerds", 10% "smart jocks", and 10% "band geeks" (or whatever other categories you want).

I probably agree with that, but also acknowledge there's no good way to make that completely objective.

In Europe, university is treated as education for adults, not your entire life. Most universities are not campus resorts like in the US, but just buildings in the city itself, students live a normal life in the city, they rent a apartment or live in a dorm, take public transit to get to places, do sport at a sport place independent of the university, etc. You can live a well rounded life that way. The university is there so you learn your specialization. Of course people make friends there, but it doesn't have to be your entire life, and the university administrators job is not to meddle with people's social lives to make them "interesting", but to allow learning.

> I probably agree with that, but also acknowledge there's no good way to make that completely objective.

Even worse, rich kids have far more means to engage in extracurriculars than poor kids.

This just means US universities are for networking and partying as much as they are for learning.