Rent control is quite common in many parts of the world. Especially New York. But investors there know the rules and choose to invest on that basis. What you are buying is really an income stream pegged to inflation, not a property. Therefore those properties are almost always positively geared and there is much lower potential upside.
Society needs to provide accommodation to those who can't afford it in a competitive market place. This is probably as important as free health care and education.
Buying houses tenanted by people with no money, to kick them out and replace them with people with slightly more money, isn't really the most productive investment.
However the idea of a landlords association is good. It could hold tenant history reports, mostly red-flags of those who have previously trashed a place. Knowing there would be a semi-public record of your tenancy behavior may encourage better behavior (e.g. paying rent, not setting fire to carpet).
