I don't know. Toyota, Ford and GM are on a scale much bigger than Tesla is for now. As it is Tesla's delivery service is contracting with UPS and UPS isn't able to give real time status updates which is causing problems with customer dissatisfaction. Think UPS could handle something bigger than 20K deliveries a year?
Plus, it is one thing to be delivering cars strictly in the US and Canada. Even with that Tesla is having to deal with different laws in different states which is probably causing all kinds of headaches. Now imagine with Toyota, Ford and GM, they are delivering to countries all over the world. Not only do they have to do with shipping logistics, but now they'd have to deal with each country's laws and language. Further to be effective selling those cars all over the world, they'd have to learn each individual sales market and the preferences it has.
Then there is the servicing problem. Right now Tesla is severely undermanned. It cannot take care of all of its customers right now and how many of them are there at the moment? 3,000? The big boys are selling a million cars a year. It would be a great capital expenditure to set up a ranger service all throughout the world, and not to mention the headache of finding qualified people and/or training them in multiple languages and customs.
All of that is a daunting task. I think the dealership model works for the big boys. It allows them to concentrate on making the cars. It leaves all the sales details and servicing to all the dealers. Tesla can do what it is doing because it is small. And even then it is having problems. There is something to be said for the dealership model.