It seems like you've forgotten the concept you invoked earlier...people get priced out. This isn't some imaginary scenario where every renter has unlimited money and will pay whatever price the landlord asks. You won't live in an apartment you can't afford (and/or won't live in an apartment that's too shitty for its price), and that apartment will remain vacant if no one can afford it. What do you think an owner would do with their empty apartment that no one can afford? Just keep raising the imaginary rent that no one is paying?