Because of competition. And not just of identical units, but also of alternative living arrangements and other more indirect substitutes. If I'm being charged

Because of competition. And not just of identical units, but also of alternative living arrangements and other more indirect substitutes. If I'm being charged $500/mo to live in my apartment, then moving in with my parents or some friends saves me $500/mo. If all the landlords raise rents $1000/mo, then sharing a space saves me $1500/mo, some of which can go to making that shared space more comfortable.