[skeeter2020]

1. the tickets are sold by TicketMaster using dynamic pricing to extract the maximum price per ticket

2. the concerts are held in almost exclusively TM venues, leading to #1

3. the concerts are produced by LiveNation, which is TM, leading to #2

4. the bands are more and more often signed to LN for their tours, leading to #3

if you need more info you can do your own research.

[Spooky23]

0. The tickets not sold by TicketMaster dynamics pricing are resold on StubHub. (Aka TicketMaster)

TicketMaster can extort the performer for a bigger cut because if the performer takes no action, TicketMaster gets the resale, and the performer gets nothing. TicketMaster owns the data, so they can negotiate the dynamic royalty more efficiently and get a yield better than resale.