Go back 10 years ago
When the Apple phone was still just a rumor. People thought Apple was crazy to think they could compete with the likes of Nokia. Most thought it would basically be a typical phone that integrated iPod functionality, and they were already too late as phones that integrated MP3 support had already hit the market.
When the iPhone was finally announced, people thought it was too big (including me) and when they saw the price thought they were crazy and thought Jobs was on drugs for suggesting that Apple might one day have as much as 1% of the worldwide mobile share - that would mean selling 10 million phones a year! They are now above 10%.
Currently the car is just a rumor, though like 2006 we're pretty sure it is a matter of when, not if. Like 2006, no one knows exactly what features it would have - will it be just an electric, or be autonomous? Will it be available for purchase, or only for per-trip / per-day rental? Will they even make cars, or will they license software to the Fords and Toyotas of the world?
Like the mobile market in 2006, the automotive market in 2016 has a lot of entrenched players that people can't imagine won't still be around in the future. Where is Nokia today? Where is RIM? How much has Samsung changed? In 2036, I am willing to bet that between the companies you listed - Ford, GM, Toyota, Nissan and VW - at least two will either not exist (not bought out, just gone away) or be a shell of their former selves like Nokia & RIM are today.
Not saying that Apple will be responsible, but the automobile market there will be completely different due to a totally different set of expectations from those purchasing cars about what features are important to them, just like the mobile market is completely different from what it was in 2006, due to a totally different set of expectations about what features are important to them. Apple doesn't have any history of making cars, but neither did they have any history of making phones. Tesla shows it is possible for a car company to build themselves up from nothing, and they didn't have anywhere remotely close to the resources Apple has to make this happen. I have no idea if they will be successful or not, but I don't dismiss their chances out of hand like you, because automobile world is about to be disrupted like the mobile world was, and a new set of players will emerge at the top.
If I had to guess, I'd say all but one Japanese car company will fail to survive long term, at least one Chinese car company will spring up to worldwide prominence, and Samsung has a good chance of becoming a major player in the market. At least one company that comes purely from the world of technology (I don't count Samsung because they make everything from chips to ships) such as Apple, Google or someone we haven't considered yet will emerge as a major player.