I've done a little research now, and I'm inclined to return most of the way to my previous view.  The number of notable foreign musicals is small compared to the number of notable American and British musicals.  There are a lot of Bollywood movies and Japanese anime with music, but I don't think that constitutes a very significant part of the story of musicals (although, obviously, we need to add some discussion of it to the main topic).  If no one can come up with a good reason for the geography tag to be on the article, we should remove it.  I repeat my original question: What good does the tag do us?