I always find these things funny, because there is a belief that all dealerships are the same (that is, the variable is simply the price of the car.) It turns out that dealership location is a HUGE variable driving both pricing and decision to buy. Some people need a car sooner than others; the dealership with inventory is more attractive. The one close to your house or work allows you to get service and still get driven to your destination; buying from a dealership 100 miles away, even with the best price, may not help if you need service that only the dealer can provide (either free or something a local shop can't do).

No question, there is much one can do to shift the power. But there is a reason why no one has yet gotten the car purchase process totally online: the dealers do indeed have some power. They control the distribution of the car to you, and they have location-based impact that, for some people, is important. At the end of the day, you are buying from one of the dealers, and if they are all above your price but you want the car, well, you either pay more than you think you should, or change your car choice.

If you don't care about the "free oil change" services or other post-sales issues involving the dealer, and have the time to deal with multiple dealers and a potentially extended process... then go for it. If you are in an area with few dealers for the car you want, however, you may find the negotiation requires a different approach than merely a PDG assuming multiple equal competitors.