I agree with most points here. However, what I don't know is the average use of CCC or unhaggle. For every 1 individual like myself who did their research, due diligence to understand cost and know how the dealership makes money, there are what, 10, 20 50 people who went into the dealership, got $1K off the car, and sealed the deal at $2K, the dealership will be making money hand over fist.
And this is probably one of the most opaque industries there is out there. As I mentioned, Unhaggle/CCC are still lead generators. 'Invoice price' still doesn't include holdbacks, marketing support from manufacturer, dealer incentives for pushing a car etc. etc.
Sorry - I have a personal vendetta with dealerships.