The U.S. (and for the most part, Canada) doesn't count. You have two main carriers and two also-ran carriers; two use CDMA, which is a dead-end, and the other two use GSM, which is not. Canada has three carriers, and two of them share a new GSM network (the third, Rogers, has been GSM for a decade).
In Europe, there are more carriers (2-3 per country) and lots more competition. As I said in a different comment, I paid €5 for a 3GB data plan for my iPad last month in Italy, whereas I would have to pay $35 for 5GB here in Canada.