You must have a place to live and you are going to be paying for that. Why not own it so that your payments actually accrue capital while you're at it?
I've run the number in the past and in some markets it's clearly cheaper to own than rent (typically where there is slow but steady increases in prices - mid-west US). For other markets, you need 3-5% asset price increases just to break even with renting after 10 years (bay area).
He was just gambling on real estate appreciation and using me to cover most of his carrying costs; I would rather gamble on stocks.
By making the rent slightly lower, the landlord is sure to get a renter to cover most of the costs. But if the economic situation declines (or interest rates rises), he can just bump up the rent to cover the increase.