Perhaps unrelated, but is the Tesla Gigafactory intending to produce "competitor" batteries, or are you assuming that GP was only looking at Tesla's? If the GP didn't get a Tesla, how would their factory be of use to him? (Actual question, not sure if there is an implication that the new factory will drive down prices for everyone).

Also, unless GP lives in an area where those sorts of garages are available, at least in the near term, they won't have anywhere to charge, which seems a fair argument against purchase. For instance, I live in south-eastern Wisconsin, and while there are charging stations within driving distance, there aren't any that would be convenient on my way to or from work, and I couldn't simply leave it at one and walk to work (or bus, because we don't do public transit here).

Known costs are known, less of a risk. It's easy enough to buy a new EV car if the other factors here are resolved, but I don't think it's unfair to say too many issues are up in the air at this point.