Because tickets are a limited commodity. A show's sold out, but scalpers and shitheads like Ticketmaster with their variable pricing being the only choice by the time anyone without bots is shopping? Guess what price everyone else is paying...

Because people aren't a hive mind. Voting with the wallet doesn't really work on limited luxury goods due to population scale.

Something like concert tickets or any luxury good is in such a low supply that there will always be enough people with more money or credit than sense.
So there pretty much isn't a choice of not buying and prices eventually getting lower. The prices of luxury goods will always be as high as possible and thanks to population scale and ad campaigns, that's going to be rather high.

Though don't get me wrong, im not advocating in defense of buying expensive useless shit. I've quit quite a few things and at least one addiction because the price rose above some predetermined limit. Just that the voting part doesn't really work anymore.