Don't give them ideas.

Have Life-or-Death duels for any CEO or landlord wishing to raise their total pay or rent. If they win, tax them at 90% income. If they lose they will die.

The real solution is that new housing permits cannot be granted until a certain threshold of low income housing is met. For instance, if 3% of the rental market is low income housing, and the city ordinance requires 15%, no new multi-unit housing construction permits are granted until the minimum threshold of 15% is met. Don't let them build their "luxury" condos until the needs of the city are met. Unfortunately, money talks, and right now the people building the condos have a lot of it.

In a market with expensive housing, that would have effects similar to simply making renting illegal: a dramatic drop in property values, conversion of multi-unit rental properties into condos, and no apartments available for rent anywhere that isn't a slum. I suppose it would be good for home-buyers, since people owning (former) rental properties would be desperate to sell, but it wouldn't be good for renters.

That is a pretty bad idea unless those average rent prices were HEAVILY localized. Like it can't be a whole major city...or even 1/4 of one.