The last/marginal ticket in the venue sells for 10x face value. The majority of tickets don’t sell for much more than face value.
Taylor Swift can’t realistically play more shows than she did during the Eras Tour, and it’s unlikely that she’d have sold a million seats in London if she were charging much more than she did.
> The last/marginal ticket in the venue sells for 10x face value.
That's only if the event sells out. The ticket should have sold for a higher price such that the demand was exactly the number of seats available.
It seems like you could sell tickets in tranches at tiered prices. It seems very tractable. I suspect artists don't want to look greedy by personally charging what fans are often willing to pay.