Renting is a market. Why would it be such a special market that every seller is guaranteed to at least break even, when that doesn't hold in any other market?

Renting is a market. Why would it be such a special market that every seller is guaranteed to at least break even, when that doesn't hold in any other market? The market rent isn't whatever it takes for every owner to make a profit. In particular, not every owner will have the same cost of capital or the same expenses. Imagine one owner who paid off the mortgage years ago and is able to rent a unit for $200 while another owes the bank 100% of the value at 5% interest and needs to charge $300 just to break even.