I don't think border crossings are really a daily occurrence for most in Europe. More common than in the US? Sure. But still not anything like a majority of users do this often, and I'm sure almost none of them are happy with having to do so.
Daily is obviously a bit of an overstatement, but Europeans are far more likely to leave their country on business and/or holiday than those of us in the US are. As a result, there is a general understanding that you can make your mobile use much less expensive by swapping sim cards. A knowledge that doesn't exist in the US (which I imagine mobile providers are happy about).
