As with the Brexit referendum, it isn't a purely clinical economic question. Yes, in both cases separation likely results in both parties taking a fiscal hit. But there are other factors to be weighed, and to some people, the economic factor has trivial to zero weight.
If the question is taken up in Canada for a third time, then "Depart, I say; and let us have done with you. In the name of God, go!". I look forward to the change in the balance of power in the House of Commons.