Not necessarily. Book of Mormon is a hot ticket right now, and since so many people are willing to see it, they've decided to jack up the prices because, well, they can. Depending on the show, a blockbuster hit with high demand for tickets (meaning many people are clambering to see it) could have higher ticket prices. With that in mind, I'd say that there are more audience members now than there have been in the recent past.
"Was uns befreit, das muss stärker sein als wir es sind." -Tanz der Vampire