Europe is not different in this regard. Usually the opera is sung in the language it was written in (tends to be German or Italian). So in England/UK most Operas are in those languages, not in English. There are some of course, and they make more of an effort now to put on things which were written in English to make it more accessible.
You're correct to compare them to Musicals though, in terms of content/storyline they are very similar, the musical style and social class of the audience (in general) are the big differentiator. You can also listen to Opera without visiting an Opera house though.
Opera is a remnant of the worst kind of nouveau riche status seeking.
This is a bit reductive and unfair - people can enjoy the music of Opera without thinking it makes them better than others.