Costs can only go up by as much as they are not regulated for. If a situation like this occured then rent controls such as exist in Germany could be implemented in tandem.
This is not really going to solve anything.
fee.org/articles/how-germany-made-rent-control-work/
At the end of the day, there’s no escape from the laws of supply and demand. The Mietpreisbremse has avoided the worst effects of rent control, but only because it has so far been ineffective. But then, a system of rent controls that is merely ineffective, as opposed to actively harmful, is probably the best one can realistically hope for.
This article first appeared at the UK's Institute of Economic Affairs.
We have rent controls in NYC. They had to be relaxed because they brought new housing construction to a dead halt and landlords were abandoning buildings because they couldn't afford to operate them.
The new rules are more flexible, but have created two housing classes, the lucky few who have RC flats and hang onto them like the grim death and everyone else who pays market rental rates.
So you've now proposed manipulating the market in two ways - price controls and higher costs through increased taxes. I get that you think this will put more housing units into the for sale market, but that will only hurt renters. You need to focus instead on making the pie bigger, not on favoring one type of demand while trying to suppress the other by regulatory diktat.
At the end of the day, there’s no escape from the laws of supply and demand.