Why is it a monopoly? I think at many venues they only sell via TicketMaster; but why have the venues locked themselves into this, what do they get out of it? Are there some kickbacks for venues or something?
I recall some other ticketing companies moving in a few years back and now it seems that Ticketmaster has regained a lot of their original stronghold. It could just be the Denver area, but they are everywhere again over here.