"Down there" being the difference. With our smaller population especially 30 or 40 years ago, these now classics never came to Canada in comparable numbers. Combine that with the same number of winters and even fewer proportionally exist still today. Add to that, that there really is only one 'sweet spot' in Canada where older vehicles, due to climate, have survived well (coastal BC) whereas the US has the southern states.
The climate, and survivability (or lack thereof) of classics further strains the automotive hobby in Canada, as sinking thousands of dollars into restorations, for a vehicle that you can only drive at best 8 months of the year is not as rewarding for many. Even just driving older trucks like ours kinda sucks. I've got this great fully capable 4x4 locked at both ends, and I'm worried to drive it in a snow storm for risk of rot, which is just poking it's ugly head in the crooks and crannies.