For several reasons. First of all, almost everybody buys a big bucket of minutes and thus they don't really think of it as "both parties paying for the call." And almost all carriers here offer the ability to not have either party pay on a call to another customer of the same mobile company.

The Euro model with a mobile to mobile call (without in-network benefits) has the caller paying *double*. They pay for their own airtime, and the airtime of the called party, which they didn't get to negotiate the price of. The US model has each party pay for their airtime, which they negotiated the price of. I never go over my minutes, so it's effectively nothing. (I have a plan that gives 500 minutes, unlimited data, unlimited SMS, unlimited picture messaging, unlimited domestic long distance and unlimited minutes nights/weekends and unlimited minutes to other customers of Sprint all for $30/month. Does that seem nuts to you? Is any European or other plan close to that?)

In the USA/Canada, mobile numbers can't be told from landlines. They are all the same and so all costs are put on the party that knows they have asked for something special. If I elect to use a mobile with airtime costs, I pay those airtime costs, including when people call me. That's because I'm the one who gave out a mobile number, they have no idea that's what I am on. If I call long distance, I pay the costs, though of course on most mobile plans and many home plans, that no longer exists.