If that is really true, I am beginning to have serious doubts about Tesla as a successfull future carmaker.
I mean, not installing ACC in Model S for some economic reason would be fine with me, but not knowing what ACC is (ACC being hardly a novelty after being available for many years in many cars from all kinds of manufacturers) really would be quite exceptional.
On the other hand that would explain many things about the contents of the much hyped (be TSL) Tech Package, which in reality doesn't offer anything even mildly special or high tech at all. At least nothing that isn't available on almost every premium sedan on the market right now.
And if they don't know what ACC is, then no wonder there is no LED headlight, power foldable mirrors, climatized seats, head-up display, blind spot assist et al.