My theory being that most EU banks don't charge much while most US banks screw their customers on the matter. Maybe it's done to "protect" their precious citizens from those nasty overseas fraudsters lol
The banks in European countries have usually cooperated in or been forced to make national, and lately European, standards. This makes transfers cheap and easy. In the US the culture among companies is to try to lock in customers. Some of the results are that checks were popular in the US for a long time after they had been replaced by debit cards in Europe, and implementing online banking for paying bills have been much easier in Europe. It's the same thing for mobile phones, where Europe had GSM and every US company had their own standard.