lots of people counter the above by saying they'd rather see less extravagant stages and have more affordable tickets. (i personally am appalled by the ticket prices, but i don't hold it against them - LoFL, it's the Rolling Stones! let 'em have extravagant stages if it makes them happy!)
anyway, the band has lots of costs that are the same no matter how simple or elaborate the stages are. security, for example. when fans agitate for the Stones to play more small venues - and at low prices, dammit! - they seem to overlook the fact that playing small venues doesn't make them any less over-the-top famous or less in need of constant security people, whom they have to pay.
"What do you want - what?!"
- Keith