Google would really like your money, but in order to get it, they'd have to spend a lot of money. The reality is that there are so many laws about IP and money that it's nearly impossible to sell music or collect money in the US. Any business that does this successfully only does so after much hacking around US-based corporations and laws. Each new country is a fresh start, and the intersection of laws between two countries is almost always the empty set, meaning that there is no scaling effect. It's like swimming to shore while being sucked out by a rip current. You die.
A Google engineer implementing payment processing rules costs the same as a Google engineer inventing the space elevator. So Google is not going to do something like launch a brand new super complex product in every country, because that's money that could be spent on something actually cool.
It's getting easier though, at least in Europe... a common currency (mostly) and an ongoing harmonisation of data protection (just started), business and IP laws. It's not there yet but at least it'll make European countries a lot easier to enter eventually.
