By not allowing incredibly devoted fans to participate in an auction for tickets, they are actually making shows less accessible for the people who want it most. It's unfair that you can get to see a performance for $50 because you happened to get a ticket, but I am unable to even if I'm willing to pay $500.
The person who can only afford to pay $50 might consider it unfair that they can't get to see it just because you can afford to pay $500.
Tickets go on sale for $100, and 100 are bought by a single scalper for $10000. The scalper now needs to sell only 10 tickets at the market rate to break even. Since he only needs to sell 10, he starts by trying to sell them for $1500, knowing he'll initially have few sales, but that he can lower his price later if he needs to.
Now what you have is tickets being sold for $1500, and likely empty seats in the theater. The show is making 1/10 the income it might have made and won't be able to run as long, so even fewer people can see it.
The larger the margin between market rate and actual rate, the fewer people who will see it, the shorter the show will run, and the more expensive tickets will be for normal people.
The smart move is for the theatre to sell all tickets at a falling price: every day, tickets for the show on day X are cheaper than they were yesterday by an amount determined by how many tickets were sold. All seats will be sold at the market rate and scalpers have little margin to take.
Problem is that everyone wants to see the major stars and won't be as interested in a different cast. Or maybe they will. The touring show opens in Chicago this fall. We'll see.
It's in the shows interest (energy, PR, etc) to have all seats consistently full.