indeed cheap loans... but of course that isn't a significant factor in rental rates, cheap loans only enable increased bidding on house prices and push up the prices ....
what drives rents up is the perceived option to increase the rent so that greater profits can be made.... as supported by rental managements who advocate for increasing rents so they get a bigger commission.
tight supply enables landlord to increase rates faster as people who need a home and perceive they won't win with plain honest competition plan to reduce competition by bidding up the rent.
these are the dynamics that make the rental market.