~5 months out of the year the average is under 7C in Quebec (Nov - March usually, some years it's more like Oct - April
)
Been using winter tires since my first car @ 16 (so nearly 20 years ago) aside from 1 year where I decided to try keeping my M+S (T/A KOs) and I shat myself too often during the first dozen snowfalls that I bought full winters in late Decenber lol.
Like someone mentionned, they put it into law now to have winters in Quebec, and I definitely agree with it.
I could see how having less than 2 months of under 7C degrees and not that many snowfalls could suck paying an arm & a leg for winters, I'm not even sure I would do it myself; massive snowfall? Take bus/taxi/metro/walk/work from home/call in sick/etc... I wouldn't chance it on all-seasons!