I think the argument in this case is the algorithm is effectively acting as a single agent that will always come to a fixed price and is actively recommending having vacancies to prevent competition.
Where as if individuals are assessing the prices they are in a sort of prisoners dilemma, if they leave a property vacant someone may lower the average price meaning they can't recoup the lost earnings when it is occupied. So their best bet is to keep a property occupied as much as possible.
Eh, I'm really not convinced they'd be effective. If they're trying, then sure whack them with price fixing charges.
I'm just not aware of any markets where these guys are dominant. You STILL have the prisoners dilemma issue, as there are tons of smaller landlords out there that definitely aren't playing in this game no matter what you're doing.
And I don't see how this is THAT much different from just doing a search for rental properties in your area on zillow and setting your rent prices accordingly. If THAT is price fixing, then how does anyone expect a market to work at all?
Where as if individuals are assessing the prices they are in a sort of prisoners dilemma, if they leave a property vacant someone may lower the average price meaning they can't recoup the lost earnings when it is occupied. So their best bet is to keep a property occupied as much as possible.