To expand on this, Best Buy and Costco still make money. Costco because you bought a membership to go in the store to buy that iPad. And Best Buy because they make their money on high margin accessories and Geek Squad protection plans.
Dealers can sell cars at MSRP and still be profitable!! Service department, parts department, extended warranties, kickbacks on financing, marking up gap insurance...
Why would a dealer sell a hot item at MSRP when they can gouge you for it?