I get that, generally speaking, the owner of a house should have the right to set their rental prices. But what is the risk associated with a property you own s

I get that, generally speaking, the owner of a house should have the right to set their rental prices. But what is the risk associated with a property you own suddenly coming under rent control? Sure, there is the opportunity cost if the market rent goes up. But do costs correlate with the market rental value? I would assume (and I could be wrong), that when you buy a property you look at the current market rental value to decide if the property could be profitable. Are there landlords who buy properties that will rent at loss because they are speculating that they'll be able to raise the rents by 20%/year (to pull a number out of the air)? Does the cost of maintaining a property rise faster than what the rent-control laws allow you to charge for rent? And yes, I get that the possibility of rental control can scare of developers. But I'm wondering what the effect is on current owners. I've never been a landlord so there is probably something I'm missing.