The Book of Mormon has played for eight months and its grosses and average ticket price have steadily increased almost weekly over that time, instead of leveling off or decreasing. If people were seeing the show because it's the hot thing and leaving disappointed, you could see that register with a trail off in gross and average ticket price after around the six month mark. But post Labor Day alone, The Book of Mormon's average ticket price went up from $145.43 to last week's high of $153.89. That means it's getting all full price sales and premiums, and I would expect that with no other heir apparent for Broadway's next big thing, interest should only continue. Personal opinion: I think it's a much stronger piece of writing than either The Producers or Spamalot, and will prove far less vulnerable than those shows when cast replacements occur.
I'm not sure what's "disgraceful" about the show's average ticket price, since with the exception of Mormon, Wicked and Lion King, every show on Broadway can be had for a discount. A new "can't get into it" hit is always good for Broadway. And it's sort of refreshing that in a Broadway climate predominately featuring jukebox musicals, stage adaptations of movies, Hollywood stars in limited engagements and revivals, Mormon has a cast of talented unknowns and its writers are the stars.
Begin at the beginning and go on till you come to the end: then stop.