> What is the cost of "meeting diverse people"…

In this case, it's self-funding. International students subsidize much cheaper in-state tuition.

Now that full-tuition-paying international students are gone, the average US students will have even harder time affording that. Congratulations.

Foreign money coming in will have to be made up elsewhere. It will be made up by raising tuition on remaining students. Schools that have a small enough applicant pool will price out their applicants and close. Likely they will be replaced by for-profit grifts that are much more affordable but don't actually do anything for the students except bilk them. The largest most international most diverse most administratively bloated schools will be fine. It's the small mostly-white rural colleges that will suffer the most.