Wouldn't matter. If they did that I guarantee we'd have a whole whack of people complaining it's too vague and can't Tesla be more precise, etc., etc., etc... Best to just accept that no matter what you do, you can't make everyone happy. Some simply don't want to be happy, they'd rather be disappointed. Personally, I'm all about measuring my expectations of anyone and everyone, including companies. That way I'm never disappointed.
That's you, what about the masses as described above? Saying "This summer" would have sufficed in the above situation. It would have been accurate (we assume) and would have provided a pretty narrow window (3 months), so there shouldn't have been TOO much antsy-ness.
Personally, I LOVE to be happy and impressed. I used to be with Tesla, but nowadays everything they say I take with such a large grain of salt that it's barely worth paying attention to. Not that I'm the center of the world, but I do think if there are more folks who feel that way, then it's a problem.