Cryptocurrency isn't actually scarce though, it may be "scarce-like" but the scarcity is an artificial property that can be arbitrarily changed, unlike gold's scarcity which is an unalterable property of reality.
In all practical senses it is scarce. It is the protocol and consensus of the people using it that makes it scarce. If you disagree, go ahead just make your own BTC and see how "easy" it is to convince other people to use it instead of BTC or some other mainstream coin. (Some people even tried exactly that...)
You can't really know how easy it might be for me. For example, if my name was Vitalik Buterin or Elon Musk or even Donald Trump, I could trivially create my own cryptocurrency and a lot of people would use it.
Creating a new cryptocurrency doesn't make Bitcoin less scarce.
At worst your coin takes time and attention away from Bitcoin, and thus takes value. At best it outgrows Bitcoin, and grows the entire space.
But that's like saying you could build your own alternative to Facebook by whipping up some corporate partnerships and venture capital. Go ahead, we'll see which one wins in the long run.
It's easier for those with the funds, and connections to manipulate, and censor discussions about other forks - and some pro-Segwit people did exactly that with the 2017 hard fork, like on /r/bitcoin, bitcointalk, etc.
Bitcoin is scarce; the consensus mechanism makes it prohibitively difficult to change the supply. It's barely even possible to do widely desired protocol upgrades; anything more is simply out of the question. The scarcity is far more secure than any fiat currency.
I think it would actually be easier to increase the supply of gold via asteroid mining than to increase the Bitcoin supply. That doesn't require consensus and will probably happen someday.
> the consensus mechanism makes it prohibitively difficult to change
This is a cultural property of the community, not an intrinsic property of bitcoin. If Satoshi signed a PGP message with a compelling call to alter the scarcity it would likely happen; maybe you disagree, but the point is that it's very possible to change the scarcity because it's a distributed computer program.
The fact that it's a "cultural property of the community" doesn't make it easy to change.
Bitcoin is not just "a computer program", it is a program and a blockchain. The same program with a different blockchain is not Bitcoin (there are plenty of those out there). Adding more supply to the Bitcoin blockchain would require large numbers of people to work against their own interests, decimating the value of their own infrastructure investments and bitcoin holdings.
It would be much, much more difficult to change Bitcoin than e.g. the supply of dollars or euros which are considered scarce enough for most purposes by most of the world. And, I contend, even more difficult than changing the supply of gold via asteroid mining. I doubt that even the second coming of Satoshi would be enough to do it (and I also very much doubt that Satoshi is still alive, or that he would want to if he was, considering his known political/economic stances).
The point is that the scarcity can be trivially changed if certain people decide that it should, which isn't true for things that exist in the real world like gold. Norms shift over time and your suggestion that it's unlikely to change is your opinion based on cultural analysis, not something that can be proven to be true even in principle.
> It would be much, much more difficult to change than e.g. the supply of dollars or euros which are considered scarce enough by most of the world
This thread is about gold not fiat money, obviously the scarcity of fiat money can change, that's the whole point of fiat money.
> can be trivially changed if certain people decide that it should
This is simply not the case - see 2017 bitcoin cash fork or Segwit2X push. At the end of the day money is a human invention, meant to facilitate value exchange between humans. So it requires consensus between the users of the money, if some fraction want to change the rules they are free to.
We went for something we found in nature with properties that were pretty good for that, but with some downsides (not absolutely scarce, difficult to transport, easy to steal) to something created specifically for the purpose.
You can't "prove" that Earth's gold supply won't increase with asteroid mining either. We can disagree on the relative difficulty of asteroid mining vs. changing Bitcoin's consensus rules, but you must at least concede that they are both possible.
Right... No matter how many people wish it to be so, the amount of gold on the planet cannot be arbitrarily increased, instead, you'd have to go to extremes likes mining astroids in space, a feat of engineering that is only possible in theory.
Gold’s scarcity is certainly not unalterable. Gold can be destroyed, increasing its scarcity. Plus we already have the technology to create gold out of other elements in a particle accelerator, decreasing its scarcity. That process happens to be prohibitively expensive, but there is no guarantee it remains so. The scarcity of cryptocurrencies and gold both depend on the actions of other people.
Yes, it's possible to destroy or transmute gold, but as you already stated, it's prohibitively expensive thus with respect to scarcity it might as well be impossible. Yes, that might change in the future but there is no reason to believe that it will.
No. Your belief that the bitcoin community will never choose to alter the supply of bitcoins is not the same thing as the properties of physics which constrain the practical transmutation of gold.
Any change to bitcoin's supply algorithm requires a hard fork of the blockchain. People have done it before but those forks are considered worthless by the community.
You're right that it is a community belief. If enough people were convinced that supply should be increased, they could fork the blockchain and move to the new chain. The change in supply would alter the price appropriately.
But that's no different to the community belief that it has any value to begin with. If everybody was convinced that gold was worthless (outside of its practical industrial uses), it would cease to be a store of value too.