I can tell you that when I rented and from what I know of landlords (cousin, brother, friends) the rentals are not much different than the mortgages. The issue for my wife and me when we were first married was - we knew a lot of people who had mortgages that were at or less than we were paying in rent. The issue was coming up with the money for the down payment and closing costs. And down payments and closing costs are still issues to this day. If landlords charged based on what they bought the home for 20, 30 or even 40 years ago (and what if anything they owed as one person alluded) then when it would be paid off they could just charge the renter for taxes and insurance. They'd be the most popular landlord (and dumbest) in the area.
The unit for sale is listed at $290,000 while the unit for rent is listed at $2,000 per month. When you add all the costs of the condo for sale, it comes to $2,400 per month. The monthly costs for the two options are very similar ($2,000 vs. $2,025) when the purchase option includes the mortgage payment ($0 down and 4.13% interest), taxes and insurance. The $375/month condo fees push that option up to $2,400.
The duration of ownership is far and away the most important factor. Let's look at the five-year mark in the comparison I described.
The person who buys the $290,000 property ends up making more than $57,000 in interest payments through the first sixty months, yet owns less than $27,000 in equity in the home (for the sake of this discussion I've assumed that the value of the property doesn't increase, but nor do the taxes, condo fees, and insurance costs). Through the first five years of ownership, he would have been better off renting the property and putting the difference between the ownership cost and the rental cost ($400 per month in the first year) in the bank, even at a minimal interest rate.