a friend showed me their budget recently, and about 45 hours of their wages go to rent each month (for a single room in a house with roommates). That seems very high to me, and their rent is considered "low" in their area (a small suburb)

Assuming they work full time, that is pretty average. The old "30%" rule is that you should spend no more than 30% of your pre-tax wages on rent. Your friend is spending just over a quarter post-taxes.