The top marginal income tax rate in Ontario, over 50%, might be a factor in discouraging mobile professionals from staying, let alone coming. The thing is, new graduates tend to be much more mobile than established professionals with families and deep roots, so they are much more likely to look with favour lower tax jurisdictions and do something about it.  

If Mr. Trump is able to get some tangible tax reform in place, the U.S.-Canada competitive tax situation is unlikely to improve.  

Canada can attract mobile professionals who are independently wealthy or who don't much care about tax rates, or possibly have decided they can't afford to have children and are devoted to sharing their wealth with others....