It's the subject matter more than anything else. The story. A musical about Siamese Twins surviving, living, and loving in a freak show isn't going to sell top-dollar tickets to the general public. Fans of musicals, sure, but there aren't enough of them to sustain a big-budget Broadway musical anymore. You have to have a much wider appeal.
If Side Show was a straight play, with a limited run, it would have stood a much better chance of being a success. (ala Elephant Man)
I don't think it's the marketing, the cast, the direction, the timing, etc.
It's the subject matter. The story.
"Jaws is the Citizen Kane of movies."
blocked: logan2, Diamonds3, Hamilton22