Yes, drive down rent. Of course, each producer in a market wants to get as much money for their product/service as they can get, just like every consumer wants

Yes, drive down rent. Of course, each producer in a market wants to get as much money for their product/service as they can get, just like every consumer wants to pay the cheapest price. That's why the role of competition amongst landlords is so important, so that their profit is driven to zero and they have no power to raise prices. People entering the real estate market to become landlords are that competition. Also, from the article it sounds like a lot of these would-be landlords/investors are having a tough go of things, and aren't in fact able to turn a profit which is why they have to foreclose. Your characterization of landlords as parasitic leaches taking excessive profit without doing any work or risking anything isn't super consistent with the fact that many landlords don't beat the market, or even take significant losses.