> 1) if 5% + inflation is above market rates then this rent control is either a no-op or detrimental because it may incentivize landlords to hike rent to maximum because they won't have have the flexibility to do that in the future if the market changes.

It incentivizes landlords to even out their rent increases over time, and to avoid sudden jumps. Especially for lower-income people, price shocks are devastating; having warning of an expected rise in prices, so that you can move or downsize with a year or two of notice, is a boon, and this kind of measure forces landlords to do that work.

> [...] because it may incentivize landlords to hike rent to maximum because they won't have have the flexibility to do that in the future if the market changes.

Relatively unlikely to have a big impact. Even without such a law they already have an incentive to raise rents as how as possible: profit.

Mostly the law should be a no-op.

I'm not sure what the argument is for why freedom of contract can't provide the "increase < inflation + 5%" provision voluntarily?

We currently have a drastic under provision of a good to the tune of 3.5 million homes in CA alone.

This under provision is not because building new homes isn't profitable, it is because realtors, landlords and homeowners are actively blocking new supply in order to extract above market rents from desperate people.

Adding a rent cap of MORE THAN DOUBLE inflation will have no affect on supply, it is ridiculously profitable to rent out your property right now.

CA would have to do something like cap rents at less than $500 per bedroom before profit margins would affect supply.

Market-wide price increases of 5%+inflation are rare; sustained market-wide price increases of 5%+inflation are very rare.

This forces landlords to do two things:

* When there is a sustained rise in fair market rent, they will need to implement that increase over time instead of falling behind, and then raising it all at once 5 years later when they realize they're leaving 20% on the table. This allows people being priced out advance warning.

* When there is a spike in fair market rent, like the 8-10% spikes of '14-'15 in the Bay, they will need to spread that rise over multiple years. Since this doesn't affect the profits of new units brought onto the market in response to the demand spike, it should have minimal if any effect on supplier behavior.

(And what happens when market clearing price does increase at 5%+inflation for years on end? Then housing will come to dominate the CPI, and the "inflation" term will more and more closely track housing prices.)