Artists don't choose to work with Ticket master. Pearl Jam and the Justice Department tried to beat them some time ago. It's a great story to check out if you're curious about how this industry works.
I don't think most people know how the touring business works, or in general the music industry. TM has built an integrated monopoly that means if you want to play the one big venue your city likely has, you need to work with TM, which now means you likely have LN producing your entire tour.