Bigger companies can get better financing enabling them to pay more. Bigger companies can claim depreciation vs individual owners who can't. Companies don't have to sell and pay transfer, estate, and capital gains taxes. Property taxes are deductible against rents, but not on individual returns.
So basically, the tax code favors rentals over ownership, and now that the private equity guys have figured out how to cost effectively manage the properties, you are starting to see the inevitable result.