That's right, there is seemingly something "indefinable" about a truly local spirit (or any local product) although sometimes one can lay a finger on why. Taking Scotch as my example too, consider McCarthy's Single Malt Whisky, an artisanal whisky made from all-Scottish, peated barley malt in Oregon. The maker is a brewer who distills on the side. The whisky is very good, and very much in the Scottish style, but it is "missing" something, I think it is missing the cold briny effect imparted to Scotch in Scotland in warehouses at or near the cold Northern sea. McCarthy's taste is close but is not quite there. Possibly the cold humid air in Scotland also affects fermentation in a unique way. Sure, there is ocean not far from even the interior of Oregon, but it is a different ocean, in a different climate in a different country.
I am not sure though that straight whiskey can't be duplicated. Canadian distillers make straight "bourbon" and "rye" to flavour their high-proof neutral-tasting whisky. They do not market these straights as such, so it is not possible to see how close these spirits are to the "real" thing. Would Ontario-aged whiskey made from the same mash that informs, say, Maker's Mark, aged in new charred wood, really taste all that different from that whiskey or any of Kentucky's best? Maybe it would, I don't know. Michter's, made from very close to the usual bourbon recipe (just accented more than normal toward the rye) never tasted like any bourbon I know, though, it tasted like Michter's. Hirsch's 16 year old Michter is close to (in fact better than) the original (youngish) Michter's of yore, and it tastes like ... Michter's, not like bourbon of Kentucky. The cold aging in the Pennsylvania vales may have had a special impact as compared to the different microclimate of Kentucky. This was Lew Bryson's theory, and Lew knows a lot about whiskey (and beer).
Yet, is this the "narcissism of minor differences"? Not to the whiskey mavens of the world, I suspect...