I agree that Canada is more polarized in recent years. I wouldn’t say within my lifetime as Quebec sovereignty was more of a dividing issue (we’re not at the point were politicians are being murdered).

That said, if immigration was becoming a major issue then you would see shifts in the electorate backing say the People’s Party that performed dismally in the last federal election.

Could that change? Sure. But it would have to be via the Conservatives and that’s a risky policy shift for them to make.