OK, stepping back 10,000 steps and flying up 30,000 feet to look at the big picture.
Blackrock (and other like conglomerates) buying up assets — it’s just organizations whose reason d’être is making money using money finding an asset class that they think will let them do it more efficiently. When the risk/reward profile of “single family houses” becomes more favorable than that for other asset classes (e.g., “apartment complexes,” “commercial real estate,” stocks, bonds), they go into “single family houses.”
You want to discourage that, you take away the incentive (so “single family houses” has less attractive risk/reward profile for the conglomerates because, say, you add regulations/requirements/responsibilities/costs for corporate ownership “single family houses”) or you straight up limit the amount of “single family houses” that can be owned by one controlling entity.
It’s easy to say “conglomerates buying up all the single family houses is bad for X, Y, and Z,” but what are we willing to do to counter it? Are there public policies countering it that you are willing to support, or just sit back and hope that individuals, HOAs, and local townships will each fend for itself (amongst their other responsibilities) and somehow be successful against conglomerates whose main purpose is to invest money to make more money? Or maybe you hope that the conglomerates will someday just grow a social conscience on their own and give up the opportunity to efficiently make money from “single family houses”?
Pulling back even more, do we want to keep rewarding “making money with money” or rent seeking more than, say, “making money from labor” or “making money from new production”? Because right now we live under a tax regime with a long term capital gains tax rate that is substantially lower than, say, the tax rate on income from labor beyond the first $40k per year. Changing that will change the incentive for “making money using money” vs. “making money from labor” in an even more fundamental way.