Scalpers would be more like sub leasers here. The actual builders build the housing, but you aren't going to pay your rent to 1000 different people who all play

Scalpers would be more like sub leasers here. The actual builders build the housing, but you aren't going to pay your rent to 1000 different people who all played a part in building it, and those builders want to be paid now, not over 30 years. So the landlord pays them all out now and consolidates the debt. Landlords provide housing in the same way the supermarket provides food. They didn't grow the food, but they did enable it to get to you.