Tickemaster is the music industry's Roger Goodell. They're a lightning rod that the entire industry wants in place to attract valid criticisms away from their own people, including the artists. Taylor gets to act shocked and appalled that her fans are getting the short end of the stick, while she's making huge money off of this. Ticketmaster's exorbitant fees and track record of shady dealings makes them the perfect choice.
Here's the important thing: If TM and LN were to be broken up, and a mechanism is put in place to foster competition, does anybody actually believe that the cost of buying tickets will go down? I guarantee you they'll go up even faster. The industry is well aware of what the market will support, both in terms of pricing and shady dealings. The new players aren't going to abandon that knowledge. They're going to exploit the shit out of it. The problem has never been the ticketing process and the agencies. It's always been the promoters, the artists, the venues, and anybody else that can figure out how to score themselves a piece of the pie. TM's just the front end we deal with.