Tickets for venues are divided up among the fan club online order system (FrontGate Tickets), the fan club mail order system (GDTS TOO), the venue, and Ticketmaster. The band/fan club actually holds the best seats, and they're the ones who determine the allotments. Brokers then get their tickets from their own allotment from TM, or buy paying kids to grab tickets from online presales and general sales.
Ticket pricing is about the market forces of supply and demand, but timing has a great deal to do with it. Early on, ticket prices on sites such as StubHub will be at their highest. Note that most of these sellers are brokers, but since everyone can now get into the act, many are also individuals (i.e., Deadheads), who are trying to make a quick buck (maybe to pay a broker so they can upgrade their seats). People who want to get their tickets early for piece of mind are going to pay a higher price - there's no incentive for sellers to lower their prices early on. However, as the show date approaches, the prices will drop, as supply is greater than demand. The absolute lowest prices will be the day before the show (and occasionally, the day of), but you must then get the tickets electronically via e-mail, and this carries some slight risk, especially if it's an individual and not a broker. Plus, if you're touring, it's not always convenient to have to find a place to print out tickets.
However, I have often been able to score amazing seats in the front center by using this strategy, sometimes just above cost. Getting GA tickets this way is typically below cost, since the brokers are now focusing on minimize their losses, rather than maximizing profits.
Now, there will always be folks with large amounts of expendable cash, who will pay big bucks for their prime tix. Then, there are those who just want to have the security of having a ticket (not necessarily a premium seat), and will pay a bit more than face early on. But, this represents the minority of people. So, if you really want to hurt the brokers, wait until 1-3 days before the show and watch the ticket prices drop. Use one of the big three companies, StubHub, TicketNetwork, and TicketsNow. You can also look on eBay. Finally, you can often find some deals (early on or last minute and everywhere in between) on Craigslist from Deadheads who aren't motivated by profit.
Hope this helps someone else.
"Show me a sane man, and I will cure him for you." -Carl Jung