Banks have essentially infinite money. The band of tenants is not competing with the landlord for the loan. If the tenants are likely to pay the loan off, they will get a loan, as well as the landlord.
I feel like you are skipping over the part where people bid for houses, a process which advantages people with more access to capital in a fairly obvious way.
In risk terms the landlord is a better bet because they have collateral.
Landlords have assets they can leverage to acquire more property, while renters have to save deposits from income that's steadily eaten away by... rent...
