To travel from Vancouver to the next principal Canadian city (Calgary), it requires 900 KM of driving and there's only really one metropolitan area of sorts between the two, meaning that you're going to be setting up cell towers that handle only so much traffic in a day.
As a result, to get service where you end up with just traffic shaping once you go beyond 6 GB (beyond that there is no real limit really), you need to go with a carrier that only services the larger cities. So in my case, my carrier services just Vancouver, Edmonton, Calgary, Toronto, and Ottawa, which are fairly dense areas with a combined population of 18 million or so, or just about half of the country's population. Once I leave the city, I have to piggyback on to other carriers however.
Hence why mobile carriers suck in Canada because the bigger carriers do not want to eat into their fairly large profit margins. They can afford to offer such plans, but they simply don't want to.
For the record, I pay $40 CAD/month ($30 USD or 27 EUR) for unlimited North American calling and text plus the "unlimited" data use.