As I so eloquently declared in my earlier post: "I know, I know, supply and demand, blah blah blah"
At a certain point it begins to border on immoral. Just because they CAN, doesn't mean they should. They could probably charge £500 or more for Harry Potter tickets in London if they wanted to, but they don't.
Also, yes, people are willing to pay that much, but these people are all probably filthy rich (or financially irresponsible). It's just another step in the direction of the gross exclusionary elitism to which Broadway is already prone. Like I said, it's just a sad situation that leaves a bad taste in my mouth.