This makes it clear that we must be careful to distinguish between the ledger (a conceptual spreadsheet keeping track of who owns what percentage of the economic community known as "the Bitcoin ecosystem" and later perhaps just "the global economy") and the protocol for updating that ledger.
We're back to this silly idea of separating the currency from from the blockchain. You can't, they are one in the same.
This "ledger" rhetoric is a paraphrase of the false idea they are separable.
The system is the blockchain is the currency is the protocol is the ledger.
Yes you could. Not to say the currency can run without a blockchain. Of course it can't.
But you did not address the essence of ZB's argument which is that monoculture in currency is absolutely desirable. We don't want multiple ledgers of ownership where different, conflicting stakes are attributed to the same persons.
This ledger cannot "economically" fail, only the protocol updating it. If that happens, we could still "transfer" a picture of the ledger (who owns what) to a new protocol that will update it. So yes, if the blockchain fail, we could, theoretically, seperate the currency (ledger) and "attach" it to a new chain.
Well I disagree, and I think this is just part of the process of recognizing that you can't separate the protocol from the ledger. Otherwise, you could simply argue that we already have a ledger (fiat) and we should import that into the protocol. Which of course is exactly what the "bitcoin the protocol not the currency" folks are saying.
You need a new currency because the currency and the protocol are inexorably linked. Change the protocol and the currency also must change. For example, one might imagine (non-bitcoin) protocols that can't work with a fixed money supply because it doesn't charge transaction fees at all.
You can't logically argue that "there is only one ledger" and still accept bitcoin because bitcoin is already creating a new ledger (as it must).
The fiat ledger is devaluing the holding of its participants. It is corrupted, debased and cannot be "imported" onto a blockchain.
So yes, we do need a new currency in our transition from the fiat world.
Change the protocol and the currency also must change.
I don't see how this is even remotely true. The protocol is not only monetary parameters. Of course you would know this but it is equally encryption algorithms, amongst other things.
Assume, for example, that SHA-256 is broken, then the protocol would have to be changed but of course that does not result in a change to the currency.
I can absolutely champion "only one ledger" and accept Bitcoin because I believe that the current ledgers (money) are corrupted and do not serve the greater good. You are therefore correct that Bitcoin must create a new ledger and it is imperative that we protect it as the one and only and not be distracted by others unless a better one comes along.