Can Trump make single-family homes affordable by banning big investors?

America’s housing affordability crisis is mostly a supply-and-demand problem: Not enough houses, too many people needing a place to live. President Donald Trump has a different idea. He wants to take on Wall Street.

Trump last week said he would “ban Wall Street firms from buying up single-family homes” to ease affordability issues, said Reuters. Big institutions like Blackstone, American Homes 4 Rent and Progress Residential have “bought thousands of single-family homes” since the Great Recession...