Value and availability don't always correlate, especially where derivative markets exist and free markets are put in a choke hold. Physical silver is a great example, as is Gold. But we're still in good times, contrary to what it feels like. The true stores of value are determined when bad times come and resources like food become scarce. That's when silver and gold show their true value. People like to remember the days when gold and silver were treated as money, but those times were also hard and resources were scarce.
If it gets that bad, I think we have bigger problems that debating on the supreme store of value.
Also worth noting is that a lot of silver and gold will get used up in space flight componentry, so the mining of gold asteroids/planets may not have the effect on scarcity that one might conclude. When it comes to resources, we humans are incredibly proficient at expanding to meet a growing supply. Finding new gold deposits in space will lead to the production of larger exploration fleets, and a larger demand for gold to meet that need.
I'm afraid this argument does not water. 16 Psyche is about the size of the state of Massachusetts. It's thought to be the exposed metal core of proto-planet. The difference in orders of magnitude we're talking about is by no means small in comparison to the demand from building space flight components. They use extremely thin films of gold on them whereas the celestial body in question has a diameter of hundreds of kilometers. The availability of gold is not a limiting factor in the building of spacecraft and never will be.
It's interesting how the "new paradigm" talk always comes around when Bitcoin is seeing it's price go up. In reality, the price of Bitcoin today and the price a year ago are both purely speculative, and speculation is like Icarus, who always flies too close to the sun. The moral of the story is to take your profits instead of trying to catch the peak.
I think the gist of the matter is that the world will always have demand for something scarce to function as a store of value. History shows that the ability of a form of money to function as a form of money is determined by the technological sophistication of a society. At some point, the technological sophistication of human civilization will render gold incapable of functioning as a store of value.