Read the book Ticket Masters. Explains how they've basically formed a monopoly via their merger with LiveNation - Ticket Master controls all major venues and thus all ticketing systems.

https://www.amazon.com/Ticket-Masters-Concert-Industry-Scalp...

Ticketmaster's primary value prop is a heat shield for artists. The artists get to blame Ticketmaster while charging the highest market clearing price, and Ticketmaster gets to make a nice profit being the 'bad guys'.

If the status quo was really a problem for the big artists (not all) then alternatives would emerge.

If you want to learn all about it, this book does a good job: https://www.amazon.com/Ticket-Masters-Concert-Industry-Scalp...