It's called capitalism my friend, it's very frustrating but it's the way of the modern world, i totally understand and agree with what you are saying, but to do anything about this would take unilateral action from all domainers involved in parking programs.
This would mean all pulling our names from parking programs and affiliate programs with the hope of getting a better deal, and i would bet my house that the guys making shed loads getting favourable ppc rates would not join in, why would they? why upset the apple cart.
You are right though what we need is more transparency, or more competition, a parking company that are not looking to cream it's members.
Parking is big business, and getting bigger i don't think it will be long before a company starts up that gives us a better deal then the rest will have to follow.
Hopefully.