Do you have evidence for your claims?

As I said, I didn't find the article or podcast I was thinking of. You're right that it may not be the tacked-on fees. Artists generally do not have much leverage against the monopoly (some artists get more say). It might be some things like platinum pricing that I'm thinking of, and how people think Ticketmaster raised the prices but the artists benefit without having to take the heat. Artists and promoters have a lot of influence over what are called the fair-value prices, the number of tickets released, whether to opt into dynamic or premium pricing, whether they can officially be resold, and VIP package prices. Again, plenty of artists don't like working with the monopoly, but I had just remembered such an aha moment when I heard they frequently benefit financially from certain practices the fans don't like.

It really depends. Artists can book out the whole venue and handle the ticket selling themselves, either through ticketmaster or another distributor, they just usually don't. Whenever you hear of one of those random big artists promising low ticket prices that's how they do it.