That's a reason why you should protect dealer networks if a company decides to start with that business model.
That's not a reason to protect those dealer networks from an upstart company that never had that business model. Just because GM and Ford made a deal with the devil 50 years ago shouldn't bind a new company to that same business model. Tesla has never had a dealer franchise agreement with anyone, them selling directly does not break any contractual agreement they've entered in to. They have no obligation to respect an agreement Ford or GM made with their dealer network to not compete.
Also as a counter point, Apple sells plenty of things through the half dozen Best Buys in my town. There's also two Apple stores within a 20 minutes drive. Just because a company sells through channel partners doesn't immediately preclude them from selling direct, it depends on the agreement they made with the channel in the first place. Even car dealer arrangements started out with the dealers protected by the franchise agreements themselves, elevating them from simple contract law to specific legislative protections came later.