Here[1] is a good summary of why Montreal has one of the highest concentrations of tech jobs in N. America. And, while Quebec citizens might have to bear a larger tax burden than other provinces, there are heaps of tax incentives for businesses (especially technology) to startup or relocate there. There are massive SR&ED (Scientific Research and Experimental Development) tax credits and other incentives that can halve or more employee compensation expenditures.
Vancouver needs to play tax catchup (while boosting technology sector wages to level out the cost of living playing field).
I am a bit skeptical that anyone would want to pay Quebec-level taxes, particularly with the recent political issues at play.
Could you offer some evidence for this? I'd love to believe it is true (as I am originally from there), but it just rings hollow.