Just like 21 million coin limit is also an arbitrary limit of human imposition. The idea behind it being a simulation of gold's supply is irrelevant, what matters for all intended purposes is that it became an immutable trait of Bitcoin due the game theory involved, just like 1 MB blocksize has become an immutable trait of Bitcoin due the game theory involved, this is called protocol solidification.

At it's inception, any values would have cut it, since satoshi was calling all the shoots. Once the creature was alive, he disappeared, and im sure he was smart enough to know (either planned or in retrospect) that those values would never change. It couldn't go any other way if the project is indeed decentralized. This is the fact only for Bitcoin, no altcoin meets the criteria, which is why all altcoins are overpriced and Bitcoin is undervalued, at any rate.