This isn't the only possible arrangement -- they could adopt the airlines' method of selling tickets cheap a long way in advance and ramping up the prices as the date approaches.

A puzzle: why don't event organizers sell tickets in advance as in the airlines' model? More generally, why don't they practice more price discrimination, especially given the professed aim of underpricing tickets (favoring their poorer but still dedicated fans)? Does the less concentrated nature of the event/venue industry make a difference?