Canada has a huge amount of firearms. The difference is legislation and regulations. No open carry, and you have to have a reason to own one (self defence isn't a valid reason, so either sports shooting or hunting).
The ones you can own and have on public land (for hunting) are unrestricted class, mostly long rifles and shot guns - not many semis (but you can still get one in 223 rem same calibre as an AR15). No handguns.
For sports shooting (handguns, most semis, restricted class) you do an additional day of training and need an additional permit for each firearm that lets you transport to to a specified location, and you have to travel by a reasonable route with no unnecessary stops. If you want to take a restricted firearm to a gunsmith, you need to apply for a separate permit to take it there.
AR15 was banned based on the culture around it. Ditto a few other firearms. Long story, I have mixed opinions on efficacy based on what the stated aims of the ban were.
Both licences require a background check including personal references, you have to declare any recent (two years I think) redundancies or divorce / seperation, need sign-off from your partner or spouse if they live with you. Mandatory 28 day waiting period, typically 3-5 months for processing.
I can go to a big box store and buy a rifle + ammunition today if I want. It's not like it's inaccesible.
Plenty of people have a good reason to own firearms. The US has an issue with regulations.