Firstly, because as things exist in the world today, we have thousands of highly funded companies using robots to snipe the ticket supply at release and create a much higher priced (3x+) market.
It's the same thing that happens with PlayStation console launches, except there's no chance of getting the experience later. The artist won't be in your city again playing the same set list.
Secondly, I don't think "concert tickets" should be classed quite the same as property per se, and this is for a few reasons:
- Concert tickets are limited edition, single use time slots you're booking with a person or group you admire. They're like stock options in that they expire.
- Buying concert tickets is a means to become a benefactor of the artist. (It's better financial support than buying their albums.) In exchange, you get a good experience.
- The act of profiting off of a ticket for a group you like should feel sleazy. Rather, in selling a ticket, I think a fan would simultaneously feel remorse for missing the concert and happiness that someone else that wants to go can see it.
These stipulations are of course if you really appreciate the art and the artist. There are all sorts of people that go to concerts -- such as those that talk loudly during the set, those that don't really care about the artist, etc. -- , and I understand they may feel differently.