That's pretty easy math to do.
Frankly, a world where Bitcoin doesn't eventually see a 2100 times increase in value is also probably a world where it doesn't become a generally-used global currency. If the argument is that Bitcoin's valuation is going to slow down from this point on, then in my mind that is basically a concession that it's not going to revolutionize the world the way that its proponents claim.
I don't think people completely understand how incredibly niche cryptocurrency still is and how much it would have to grow before it overtook fiat currencies.
Of course, the question is whether BTC's utility actually is going to increase the way its proponents claim (which I am skeptical of). But if it did increase, it's hard to imagine an increasingly limited deflationary asset that's going up in utility value wouldn't also see proportional price increases.