That opened up a flood of money to 18 year olds going to college, which in turn led to the colleges massively expanding their offerings.
Colleges in the US don't just educate. They are also the minor league sports programs for most sports in the US, and they provide luxury benefits like gyms and movie theaters and so on.
They can't go back now. They can't just stop doing all the sports with all the fancy equipment they bought, they can't just get rid of all the luxury housing and movie theaters and so on.
So yes, the US is pretty unique in this respect.