> Sure, tenant protection is, but “especially rent control” is wrong
It depends how you're measuring. If you mean by "amount of net cost / lost income to property owners" then sure, it's not especially anything because it's exactly anything to the degree that it does that.
But if you measure in terms of value for money, rent control sucks. Requiring landlords to have functioning clean water costs them money, but it also makes them money -- tenants are willing to pay more for an apartment that isn't falling apart. Some things may cost more than they benefit the landlord in making the apartment more valuable, but at least they may come closer to break-even, and the cost in incentive is only the difference between the two. Rent control is pure dead weight loss.
Of course, this is also the argument for why most of the other regulations aren't needed, because anything above break-even would get done anyway -- you don't need a law requiring someone to improve their building in a way that results in a net profit. The apartments that become unmaintained slums are the rent controlled ones, because the rent is sufficiently below market that the tenants would suffer the flaws rather than moving out.