Technically, the number of high school graduates dropping wouldn’t have affected colleges yet if enrollment rates kept going up, but they have also declined (only a couple percent for now, but I bet that trend continues).

https://nces.ed.gov/programs/coe/indicator/cpb/college-enrol...

Also, seeing only 40% of high school graduates going to college is a wake up call to how much I don’t interact with people outside my bubble, because I don’t know anyone whose kids didn’t go to college in the last 20 years.