"a Tesla", not "all Teslas". And of course "should" not "will". And so on. If his press releases are to be treated like contracts that he can be held to, then the verbiage needs to be parsed as if his words were contracts.
That's just not going to go very well for the people litigating that he made false claims. Which gives the impression that the litigation isn't so much about punishing the wrongs he has committed, as they are about punishing the person that no one likes.
Maybe there are other tweets that are better examples of your argument, I'll wait to see if they come up in any of the umpteen fluff articles we'll see over the next few months. In the meantime though, this seems more than a little unfounded.
2018: "By next year, a Tesla should be able to drive around a parking lot, find an empty spot, read signs to confirm itβs valid & park." https://twitter.com/elonmusk/status/1057690425710891009
2016: "In ~2 years, summon should work anywhere connected by land & not blocked by borders, eg you're in LA and the car is in NY." https://twitter.com/elonmusk/status/686279251293777920
It won't be hard to demonstrate some purchasers factored these claims into their decisions.