But given the choice between smaller and cheaper houses and larger and more expensive ones, they almost always choose the larger, more expensive ones.

The university in town is over a hundred years old, and many of the dorms are that old too. Most have no air conditioning, and have insufficient power for a resident to add a window air conditioner without special approval.

And the parents and students describe them as, "practically unlivable", "bad for the students' education, and all of that. There are numerous schemes around to get that special permission. And many scheme to move out ASAP. These are folks borrowing tens-of-thousands of dollars to go to school, and yet still go even deeper into debt for better housing, when the cheap option is right in front of them.

100 years ago no one would have thought twice about the exact same conditions. I doubt anyone would have thought twice about it even 50 years ago.

People just expect a certain level of amenities, and are willing to pay to get them.

I worked in office without AC under roof in summer and it was not just less comfortable, but productivity really went down measurably. I dont know how hot it gets there, but it can be so hot they are at disadvantage against students who dont live there.

I also stayed in house with bad insulation and it affected my health. 100 years ago, my health would be affected the same way whether better house would be available or not.

Maybe they are all irrational. Or maybe those dorms are really in bad shape.

The point isn’t that air conditioning isn’t better. It truly is. It makes people’s lives better.

The point is that it is a somewhat new amenity that people value and are willing to pay for. and that makes housing more expensive.

AC doesn't cost that much. Especially for a dorm situation, it should be less than $10 per person per month.

Almost nothing else needs to be upgraded.

And being too hot definitely impacts the ability to focus.

Is the university housing really cheaper? At my university it's 2-3x market rate.

50 years ago it was cooler and everyone grew up without AC, they were used to it. That's not the case today. It's hotter and people grow up with AC and are not accustomed to living without it. The bar has moved.

Maybe people don't want those houses; maybe people are happy to move somewhere less prestigious to get the house they want.

> Maybe people don't want those houses

It's not clear what kind of houses you are envisioning.

Go to Zillow or Hotpads (rentals) & search for less prestigious homes. You still don't get places that can be afforded with a HS Graduate income.

tl;dr: People can't move out in their 20s because of math.