It may be that the App owners haven't created the Apps for regions outside of the U.S., or may have to do with licensing content in different countries, local rules and laws... or Apps could be in progress.
Unfortunately, for each App, there could be one or more reasons. I can't speak for the Apps owners in that regard.
I see that our friends below the border can buy apps and have a broader range for their tv. How come we canucks can not get the same access.