You don’t know how your landlord got the property you’re renting. He may purely and simply never bought it. Or he bought it when it was costing nothing for him, or on the reverse a lot which prevents him to sell. Or selling it would generate massive tax for him. Or it is a diversification strategy. Etc.
And to say « renting is roughly as expensive as my mortgage payment » to justify to buy is a very common and very bad argument that is built on a misconception of what is at stake.
When you buy a property, being a flat or a house, you have costs associated with it. A lot of them. Costs associated with the purchase and costs associated with the property.
First of all, you’ll have to pay some sort of one-off real estate tax when you buy. Then you will pay all the interests of your bank credit (which are higher the longer is your credit). Then you will pay all on the on-going real estate taxes. Then you will pay all the costs of the property itself (all the on-going things a renter do not have to pay, all the big 5-10 years maintenance tasks like frontage restauration).
So renting is bad only if it is costing more than all those costs during the period, minus the real estate price increase during the period.
I don’t know where you live but in a lot of big cities, it is actually way way cheaper to rent than to buy.
The truth is most people do not really look at the proper numbers when they want to justify to buy a property because there is a lot more involved in being the owner of the place than what people want to admit.