Then you'd have a case for deceptive marketing, perhaps, if your "reasonable interpretation" is that advertising "full self driving will be available with this hardware subject to regulation" but your literal interpretation of the caveat is "but not to you, ever".

Whether their marketing language is included in the actual contract is irrelevant. If sales people and Tesla sell cars based on the idea that a Tesla is better because you get software updates and added functionality down the road (which they do), courts would most definitely side with the consumer.

Not to mention the fact that courts also tend to side with consumers when it comes to "implied contracts". If every car sold has and still does get updates on a regular basis, Tesla can't just not give the same to some customers.

Now, there may well be a provision allowing in the contract staying they have a right to deny updates if you try to reverse engineer things, but otherwise, they would need to go through the courts to go after someone for breach of contract. You don't get to take the law into your own hands when you suspect someone of wronging you.