I also don't understand the reasoning. If you're serious about a currency becoming a major player in the world, you'd at least try to keep the expected single unit value in the same order of magnitude as existing currencies. That's also what was done with the €. Once it exists it will lead its own life and establish natural exchange rate levels, but 21M can never do that.

In any case, we can always correct it. Just create a new currency, which is not minable, but only obtainable by exchanging BTC. The BTC that is exchanged will be lost from the Bitcoin circuit.

You could think of multiple coexisting virtual currencies, each based on its own economical model.