Really now? I've always found negotiation works better, as long as you're willing to take some time to do it right.
As an example, AWS's one simple price structure for bandwidth is way above what you'll get from most other providers given some negotiation. Of course, your negotiations with other providers will start higher, but you can get em down substantially.
I don't claim that Google's TV ad buying system is optimal, but it's likely a better deal than the one offered-up to an ignorant buyer.
I see a parallel to the fixed-price used car lots. While a good negotiator can get a better deal elsewhere, an uninformed buyer can be somewhat assured that he's not getting ripped off.
As an example, AWS's one simple price structure for bandwidth is way above what you'll get from most other providers given some negotiation. Of course, your negotiations with other providers will start higher, but you can get em down substantially.