Anecdotal data point: For a while, AT&T had an North-America wide plan for $~40/45 for month with 10G LTE with the rest being 3G. I kept this in Canada because there would be nothing close to this there - it was cheaper to use the American service.
I've always used my own phone with prepaid plans and the cheapest plans in Canada are awful compared to the cheapest plans in the USA. I also lived in the GTA, not some remote village.