Also, consider that the desire for greener pastures is a very top-down cultural thing in the US, that's not always true world wide (though, it increasingly seems that way.)

By number of students, most higher ed institutions are community colleges, which are (for the most part) low on the BS and extra fun. For profits, and a growing number of 'bootcamp' type schools also fit in this area.

However, 4 year schools (starting off with good ol' Harvard) completely dominate the idea of what higher ed is like. Employers still revere 4 year degrees and a "big name" still has its advantages. Many students grow up thinking that's the only/right/best option for them - so between dozens of essentially equivalently good schools (i.e. The "Top 50", and arguable the top 100-200 too), students pick on factors other than learning.

A few months ago, 538 wrote a fun piece called "Shut Up About Harvard", which is worth a read. https://fivethirtyeight.com/features/shut-up-about-harvard/