@Phil from CA:

It's likely that my landlord deducts the mortgage interest on *his* house, but that has nothing to do with the complex(es) he owns. Depreciation, Amortization and the deduction of business expenses to determine net profit are standard aspects of the tax code that would remain unchanged even if we eliminated all existing subsidies to homeowners. My landlord depreciates his garden apartment complexes using the same tax code that Chase uses to depreciate its office towers. It's an investment activity completely separate from the single-family market. Commercial property developers do not take out mortgages through Fannie Mae or Freddie Mac.

Homeownership subsidies do not create any kind of "halo effect" for renters. In the long run, the reduction in demand for rental units actually results in less housing choice, since fewer apartments are constructed.