The problem here is that you have to consider the alternatives. One strategy would be for Toronto officials to deliberately set about making the city a worse place to live. They could make the buses and trains run less frequently and pick up the garbage less frequently, and use the savings to set giant piles of money aflame on Sunday mornings. That would reduce demand for Toronto living, and thus keep single-family homes affordable. Alternatively, Toronto could adopt strict rules against redeveloping single-family homes into multi-family structures. That would create a situation in which even fewer people are able to “remain in the core” since the core would contain fewer housing units.