Detour Tickets posted this on a Yahoo! Group, and I found it interesting...thought I'd pass it on:
Promoters have to buy a show that is coming to town. They usually have to put a 50% deposit down to secure a show. Then they have to rent a facility, a PA system, a stage if the club doesn't have one, a lighting system, pay for staff and security, and then cater to the group. Not to mention the beer and water and any sort of advertising for the event.
A big reason that a lot of shows skip San Antonio is because promoters use a presale method as a way to judge if they can pay for the show. San Antonio is known as the "walk up" capital of the touring world. We are the only city that will presale 100 tickets and have 3000 people walk up the day of the event. This scares a lot of promoters and they won't even take a chance on booking shows. So the next time you want to see a show, help out the system a little bit by buying your tickets before the event. I'm not saying this to just promote my business, I don't care if the event is ticketmaster or star tickets. It's all the same and it does matter.