1. Generally speaking, I think it’s designed to benefit the landlord. The less turnover the management has, the less money they lose during the in between time when the apartment is not being rented by anyone. Except in super tight/competitive markets, tenants might prefer to rent “at will” without a minimum term lease so that they can decide to move at any time.
2. What do you mean by “short of suing in court”? Any recourse the landlord would have would be legal in nature. If you mean something that’s not legal, well, I guess they could send threatening letters or something, but if they really want to make sure the tenant pays up, lawyers generally need to get involved. That does not, however, mean that it will end up literally as a civil case in a physical courtroom.
3. The market sets the rent. If the landlord sets the rent arbitrarily high, the tenants will all move elsewhere.