You raised a good question. As I've been thinking about the cost-sharing issue for the last couple of years, I realize that one of the mistakes I and my colleagues in health economics made is that we didn't look at the response in taxes at the federal and provincial level after 1977. So you couldn't go into the literature and find an answer to your question.
There's a good Ph.D. thesis there, though, for somebody to go back and look at what actually did happen to federal and provincial taxes to see if the feds actually reduced all of the points they promised and if the provinces did the opposite.