However, properly designed cities like Houston, TX are well-poised to take advantage of self-driving cars. Very soon car ownership won't be necessary even in sparse cities, but with all the advantages of having a lot of living space and cheap housing.
Nevertheless, I imagine this is an unusually salient issue for us. I imagine for the average Canadian emigrant, the fact that the US offers a greater quantity of better quality, higher paying, jobs, is a much bigger contributor than urban planning.
A big difference I would say between a place like Tokyo and most urbanist cities in NA is that public transit is overwhelmingly the default here. My experience is that even in Vancouver or Montreal, it wouldn't be strange to have an acquaintance or relative who lives in one of the extended suburbs or a neighboring city, and for whom driving is default.