You're incorrect to say that people didn't like the show. As proven by this forum (and other word of mouth I have heard) those who have seen the show enjoyed it, some more than they thought they would. Furthermore, it wasn't like it was panned by the critics either.
But, the issue is that the concept in and of itself is a tough sell, and I feel that the producers and the marketing team didn't give it their all on this one at all. This is a show that had an Oscar winner in the cast, and a show that has a score written by a man who has a cult following of fans who feel that he can do no wrong musically. Those were two of many avenues that they should have been exploiting in order to sell this show with a tough concept. However, they didn't do anything even close to those two things I have mentioned.
And, I am sure that you're going to say that they have mentioned that Trey is in Phish. You're right, they have, but to the wrong audience. Those who follow Trey's music both solo and with Phish, had no clue that Trey was even writing a musical let alone the fact that it made it to Broadway. Like I said before on other threads, I have been to concerts where I have mentioned to people in passing if they have heard that Trey is writing a show, and they have said no. Also, like I said in other threads, these are people that would travel in droves to see his work.
"If you try to shag my husband while I am still alive, I will shove the art of motorcycle maintenance up your rancid little Cu**. That's a good dear"
Tom Stoppard's Rock N Roll