Tchaikovsky may have done something that was "pop" and "commercial" for its time, but I know two things: 1) He basically ignored the source material ("Tales of Hoffman"), and 2) it's become popular because it's such a popular show piece with the dancers -- they get to show off in a way they don't usually get to do.Although "Nutcracker" is a bit of a funny one, because Tchaikovsky HATED it. He went out of his way to purposefully do something that was pop and commercial, trying to show how awful he thought that music was, and then it became one of his greatest hits.