Has Ticketmaster and Live Nation become a monopoly?

In 2010 Live Nation acquired Ticketmaster. Did it lead to the largest monopoly in the United States entertainment industry?

Background

Taylor Swift has been in the news recently. She has announced a world tour. The ticketing system for her tour was handled by Ticketmaster. Due to a large number of people who wanted to buy the tickets of Taylor Swift at the same time, the server crashed. It has been already been identified by fans that this was a monopoly in the ticketing industry that Ticketmaster was having. People who came to buy tickets of the Taylor Swift concert have shared their experiences of how they encountered several glitches while buying at Ticketmaster. They waited for hours in virtual queues. What happened that led to this complete collapse?