Historically no, they're not. Paying for a concert before you saw it was unheard of 150 years ago, and your ancestors would have considered you a mug for giving over your money before you knew if it was going to be a good show.
The norm for human history is that you see the show first and then decide afterwards how much it was worth, hence artists passing their hat around the audience. Bad shows got no money, which is how it works for literally everyone else today. We get paid at the end of the month, not the start, and bad enough fuckups get you fired.