Probably because the service Amazon and its various skills provide plug into a lot of localised data, as well as different languages and/or accents so I'm guessing they don't roll out until they have all that (or most of it) pinned down. Mine has a British accent and everything I can access is largely tailored for the UK, including the selection of info it provides if you tell it Good Morning. It's a personal assistant but it wouldn't be very personal or very assistive if everything it did referred to the US and that wasn't where you lived.