That and the fact that C-Will buys them all up as fast as he can.The biggest issues today are the "pre sale" ticket sales. If you are a member of a fan club you can buy tickets before the general public. If you are an American Express gold member (or whatever they call it) you can buy tickets before the general public ad nauseum.
By the time tickets are made available to the general public there are barely any left to be sold. That's how a 2 night stand of Taylor Swift can sell out in five minutes.