No, it is not "unreasonable" for a prospective owner to be worried about whether they are getting the new upgrades or not.
But it is in the sense that Tesla has a very different "model year" framework than every other car manufacturer out there. If they were employing the "waterfall" approach with a bunch of changes at a certain time of year every year then ok. But they don't. They are nimble opting for the "agile" approach. As soon as you say "great I got the chip" you are probably missing something that will come the next month, or the next, or the next, ad infinitum. I mean people are going to feel the way they feel and nothing anyone can do about that. That said, I do think it's unreasonable when it comes to Tesla.