Karaoke Revolution question.

Does anyone know why no showtunes are available for the various Karaoke Revolution games?

Maybe it's the people we know, but many at the party holmes_iv this weekend--and for that matter, at previous parties held by monkeygod and mysticysm--really wished for showtunes. (bedfull_o_books, was one of them, of course.)

I can't find any answers to this on line, so I thought I'd throw the question out there for speculation. :)