Once thing I've noticed about Bitcoin is that there are many "alt-coins" that seem to deliver better on Bitcoin's promises from a technical perspective, but those coins are forever stuck in Bitcoin's shadow because BTC has that first-mover advantage. And as a currency, the first-mover advantage is HUGE, because who wants to convert their investments from a hugely popular coin to one that could disappear tomorrow? So…
This lack of governance as well as scarcity consensus is by far the strongest mechanism to maintain a scarce supply that we have in existence. It is not totally infallible - maybe a superhuman AI could social engineer the entire bitcoin community to increase the cap. But it is the best I can imagine is possible. The network effect of more people buying into it makes that 21 million meme stronger and stronger, and satoshi being "gone" reduces the risk that he comes back and declares that he has "changed his mind". Even if he did do that the core 21 million devotees will fork the coin to a 21 million and that will be the truly scarce bitcoin.
Therefore, this is the most securely scarce asset in existence.