Look, Coldplay are at the apex of their commercial popularity right now. If they charged the 30-40 bucks a ticket (and I agree with all of you that it should be more in that price range) - pavilion tickets would still be going on ebay for around 100 bucks a pop.
If the market is there, why would any band consciously say - screw it, let the scalpers have the extra money.
These shows will all sell out. Everyone in here seems smart. Its just simple economics. They might not be worth that much to you, and thats fine. But they can earn the money for themselves, or they can be "nice", charge less, and send 10-15 million dollars into the pockets of scalpers.