Protecting One's Turf

Automobile dealers are worried about Tesla's electric car.  I'm not sure whether they are worried about the car itself or the fact that Tesla plans to sell its car through its own network; they do not plan to use dealers as all other car manufacturers do.  One reason why just about all car manufacturers use dealers is because state laws require it.  So, the dealers are lobbying state legislatures to make sure that the only way Tesla can sell its cars is through dealers. That's how the car business has worked since the beginning.  Why should car dealers have to change their modus operandi just because a new kind of car has entered the market?