Union jobs. In right to work states those 3 man crews are replaced by a automated system on a truck.
Or just burn everything that will burn as power plant fuel.
Where I live, there's always cars parked on the street, so there's really no place to put a wheeled cart for the automated truck to pick it up. So, they usually have two guys on the truck, one driving, one to jump out and move the cart to a position that the truck can grab it. Then after they empty it, they leave the cart laying in the street. This is repeated three times on pick up day...one truck for trash, one truck for recyclables, and a third truck for yard clippings.