Prices are set on the margin, you need a few landlords to start to feel capital pressure to drop rents.
Yeah, I can't imagine there would be any unintended consequences to that.
In what world does raising the cost of providing housing cause landlords to reduce rents? More likely it causes landlords to stop renting. See the consequences of the rent control regulations in NYC, for example.
Low availability keeps prices high with no need to worry about things like quality. There is therefore no incentive to build to increase supply. When a market is this dysfunctional, state intervention is the only way forward. Build publicly owned housing and rent it affordably.
This probably won’t happen either, because so many in government are also landlords.
Edit: Wow, so many downvotes for advocating public housing.
So far, they've use the latter option, and that's most likely because the first one is hard: if the cartel controls the market and keeps the prices high, new investors have no incentive to join, they'll make more money if they don't.