The unspoken assumption is that it's affordable if you have roommates (or a solid dual-income household). I have a place in Providence, RI and commute to Cambridge, MA by train (38 minutes to South Station via Amtrak, double that via MBTA). It's a shorter commute than when I rented in Brookline. Because of all of the Boston-area colleges, students set the standard. The housing stock is higher quality (and lower price) once you escape Boston/Cambridge, where students will live in any sort of derelict apartment, and use loans to pay inflated prices for the privilege. Boston has many things going for it, but the housing market is a real problem. Don't get me started on "broker fees"...