Why assume you can't use a bike to shop at Costco?
I can do a week's plus worth of groceries for two adults in one trip on my touring bike since I have a big front basket, paniers, a large flat back rack, and a backpack. I even once took a mattress home by bike. Add a trailer and I could easily load enough groceries to last beyond a month, or cart several kids to school, same as a car.
Moreover - and this might blow your mind - but did you know that Costco doesn't have a minimum spend? It's perfectly possible to actually opt to buy less on one shopping trip! I pass a Costco every time I go into the office, as do many in the suburbs, and frankly, I'd rather grab a few things here and there on a random slow weeknight than fight the weekend crowds just so that I could do a month's worth of shopping in one fell swoop.
But in a way you're right - few people in Canada now will switch because they are conditioned to believe a car is a necessity rather than to be thankful they can afford such luxury. I have a feeling the next generation won't be so lucky, but whatever, who cares about the poor or young so why build infrastructure that could help them out?