http://www.washingtonpost.com/opinions/charles-lane-tesla-ta...
http://www.washingtonpost.com/opinions/charles-lane-tesla-ta...
[0]http://www.thisamericanlife.org/radio-archives/episode/513/1...
Just because manufacturers can average it out across all dealerships doesn't make it less true, and obviously dealerships can never make a car cheaper, all things considered.
There isn't a lot of margin in cars anymore, but the cost of the car isn't the actual cost. There is lots of back-end money that determines the real cost. (just like PCs -- a big PC buy is own or lost over who Intel gives the biggest rebate to)
The only real exception is in a really bad economy where a dealer gets surprised by the evaporation of demand for an overstocked unit (ie pickup trucks in 2008-9). In those cases, they may sell vehicles at a loss for cash flow -- they borrow money to buy those cars in the lot.