I think it's more a lack of opportunity to utilize a second language.  If you spend any length of time somewhere where, yes, you can sort of get by with English, but it's not the native language, you really start to want to learn more.  In the US, your opportunities are quite limited... Mexico or Quebec are your only major options, and that's a lot of travel for many people.  From Padova where I am, on the other hand, I can be in Austria in 4 hours' driving time, Slovenia in 2 hours, Croatia in about 3, or on the other side, France or Switzerland in a bit more than half a day's drive.