I don't mean to hold up Yanni as the best there is. But, as modern musicians go, he's very good. Americans today don't have many opportunities to hear good music, but it's interesting that when they do hear it, they tend to remember it. Having the movie for a springboard helped make it popular, but what really drove it was the fact that it's good music by a skilled composer. The sound track of the movie contains a lot of other good music.
People hear snatches of it in movies and whatnot, and they like it and remember it.
I first heard it as the theme music on a TV program where a professor discussed modern history. I first heard a snatch of it in a commercial for the Chrysler Cordoba featuring Ricardo Montelban. I remembered it because it's strikingly good music. I remembered it long enough to find out where it really comes from. This has happened to me often enough that I've learned I don't have to depend on snatches in movies and commercials to hear good music.