Fighting a war against the US is futile. Not saying it should be annexed but if it has to be anyone then it may as well be your neighbors who have a lot in common with you. Life in Canada would no doubt improve if it was a US territory.
Nobody ever invaded another country to improve the life of the citizen of the other country.
Countries get invaded to increase the power of the own country and that implies a less favorable outcome for the invaded country.
But what the duck are people (including me) even discussing here? Within a year it has come so far that the US government alienated one of their most important allies and people discussing the possibility of a war against them.