Ticketmaster has exclusive deals with artists and venues. Artists not signing deals with Ticketmaster lose access to venues, and venues not signing exclusivity deals with Ticketmaster lose access to artists. There are enough of these on both sides that neither wants to lose the other so they sign. Side note: I worked at a small ticketing software shop circa the Ticketmaster/LiveNation merger. The CEO got a call from…
~15 years ago, I was working with venues to see how we could handle ticketing, etc. They ALL had exclusive deals where the venue could ONLY sell online through TicketMaster and then TM would handle ~100% of the back office reporting, tracking, etc and even the onsite credit card processing for walk up sales.
It was one end to end system/suite and to replace any of it, you had to replace ALL of it once the contract was up. Not a fun space at all.