Scarcity isn't just about the supply. It's also about the quantity demanded.
If adoption doesn't pick up, then bitcoin will not become more scarce, and none of these calculations that you have made would matter whatsoever. I also think that the assumption of everyone in the world holding equal amounts of BTC is not a valid one, as that would pretty much never happen.
But I understand where you are coming from in terms of your concept of "true scarcity", and I agree. Given the fact that fiat doesn't have a limited supply the way that bitcoin does with a capped supply, it can be difficult for people to see the advantages that bitcoin has regarding its function as a store of value compared to that of fiat currencies, though it is be apparent to many BTC adopters.