Taylor Swift is a nice-ish person and wants her fans to think they can buy tickets for her shows at about 25 bucks because that’s a lot of money for a 12 year old and she does not want to alienate her fans.
Her manager is an evil cackling bastard and wants to get as much as he can.
He knows if he sells all the tickets for 25 bucks he will lose money in the tour and the people who resell the tickets for 2000 will make 1975 dollars profit.
So he does a deal with ticketmaster.
They will sell 100 seats at 25 bucks, then announce “wow that sold out quickly” and then pretend that the other 5000 tickets they have are sold, and then resell them on secondary sites (ie ticket master is actually selling you orignal tickets through secondary markets).
Then they give the cash to the evil manager who twirls his moustache.
All the rest, the adding extra charges at end of sales process, the ridiculous rush to buy at a given moment in time instead of some auction or lottery, the whole thing of backhanders to venues, all that is secondary to enabling Taylor swift to take a huge cut without seeming like a evil moustache twirling money grabbing manager.