Saying landlords are renting and then subletting makes it sound like they're double dipping, just a passive middle man contributing nothing. They're not renting from the state, they're the owners who take on all the risk and other costs associating with full ownership. They pay for maintenance, they're subject to value changes in real estate markets. They bear the cost if someone builds a dump next door and tanks their value. Their asset is very un-liquid. The tenant can walk away from the property somewhat easily, but the landlord has to find a buyer.

Of course, some landlords actually do nothing. As long as we have a healthy competitive market where people can relatively easily build new housing, this competition would punish landlords who don't provide a good product. Unfortunately in a lot of the US building new housing is very difficult due to NIMBYism, zoning restrictions, and sometimes too harsh environmental or historical review.