That seems like correlation without causation. Your explanation is a possibility but there could be many confounding factors.

Could also be something else like maybe Canadians have had more exposure to other corona virus pathogens in the past so they have better overall immunity to the current corona virus.

https://www.cell.com/cell/fulltext/S0092-8674(20)30610-3

Edit: for some reason I am having trouble making the above link work. If you will click on this link to a video by Dr Eric Berg, then look at the notes below the video and click "more", the link to the research is in those notes and it works.

From the above research: Importantly, we detected SARS-CoV-2-reactive CD4⁺ T cells in ∼40%–60% of unexposed individuals, suggesting cross-reactive T cell recognition between circulating “common cold” coronaviruses and SARS-CoV-2.

A year or two from now we will know more. How many ultimately get it, no matter how they practiced mask wearing and social distancing. There is a difference between slowing transmission and preventing transmission. I'm not convinced we can ultimately prevent transmission.

If a person is ultimately going to be exposed, no matter how careful they are to avoid it, then the best primary focus to me would be to get healthy with a healthy immune system to fight it off. Putting off getting it is not the same as never getting it.

John