Your hypothesis doesn't hold water. Slapping a foreign buyer's tax on housing in Vancouver resulted in a sharp drop in prices, but once the adjustment has been made, prices are again zooming up.  The issue is growing demand and lack of supply.  In Vancouver the lack of supply is caused by the mountains reducing the amount of developable land.
The issue in Ontario is exactly what this article stated. There has been fairly strong construction but of the wrong type.  People still want to raise their families in single detached houses, not condominium apartments, but the Places to Grow Act requires increase in density regardless of what the buyers want.
Wynne, of course, refuses to believe she did anything wrong.  Our social justice warrior is resorting to xenophobia with the non-residence tax, i.e. blaming the Chinese for the problem instead of letting the market work.