It's off-campus housing that the college rents. If they don't rent all spaces in a building then it's beyond anyone's control.

Here in Los Angeles, these types of situations often run into each other, and I've heard the same in other super-expensive places.

I didn't enjoy living with 25 year olds a few years ago. My landlord simply put in the first people who looked like they could affford a spot without much regard for anything else. They were priviledged and entitled and expected me to tiptoe around them while they blasted the TV past 2am on weekdays.

At the same time, I'm not pro-isolation or exclusion in any sense. Exclusion based on age is not cute or pretty, although I think having some time with people in the same place in life, with the same struggles is a good idea too.

I am super happy to now be in my own apartment for less than $400 more than the room I had.

I DON'T think the situation is unique, just not discussed. Probably 5% or so of students are older than 30. If they're single, they'll take the cheapest option if they can stay in student housing that's subsidized.