It would indeed be excellent city planning to do what you are suggesting. Other ideas include taxing vacant properties; restricting immigrants to ownership of a single property for N years; taxing immigration more heavily and investing in municipal infrastructure; or following Australia's lead and restricting non-residents to the purchase of newly-built housing.

And it's an great question why so many cities fail to take these steps. My guess is that inertia wins partly because it becomes politically inexpedient to blame immigrants for anything once cities have a certain percent of non-native residents, and partly because rising home prices make older homeowners happy while pushing the marginalized and disaffected younger voters into other ridings.