The apartment building, like many, many other big apartment buildings, is a privately owned real estate business. Giant land companies own such, often holding a claim (if not an outright deed) to more than one place. In order to turn a profit, they have to be mostly rented. That can be difficult to do if there are other places around in the same price range.
One way to keep rent coming in is to rent outright to whoever will pay whatever is asked, which is the normal thing to do. In addition, a landlord can latch onto a government housing contract. In that deal, there are government guidelines, such as what is a fair rent for the apartments. If someone doesn’t have enough money to pay that, the government will add enough to cover the cost, provided the landlord does paperwork.
Now, the government doesn’t just hand over a bunch of money, especially if it is a big place. The government sends around inspectors to see if it is livable. The citizenry gets upset if it’s learned the government is paying for things that aren’t worth the price. A good percent of the apartments in the building have a subsidy. The inspector is coming soon. The landlady wants the place spiffy. And, yours truly has no hands.
One always needs a “Plan B.”