The crappy student apartments where I went to school housed upper-class families in their day (before suburbanization). It happens. Deteriorated grandeur has a certain charm.

More to the point, there are plenty of homes that were affordable and in disrepair not long ago, that are now going for $1M+ in exactly the same physical shape. San Francisco’s problem is definitely not that its housing stock is too nice.

That isn't even true of many cars. 20-30 year old luxury cars sell for tens of thousands -- which might be cheap or comparable to new low-end car, if you don't consider cost of ownership

Agreed, it is complex. I'd argue, though, that older apartments in nice neighborhood usually rent for less than brand-new ones.