I don't find this a wholly satisfying position (and I say this even as someone who's generally a blockchain skeptic). Concretely, this argument conflates agree

I don't find this a wholly satisfying position (and I say this even as someone who's generally a blockchain skeptic). Concretely, this argument conflates agreeing on a set of rules with agreeing on an arbiter to determine the application of those rules. Those aren't the same thing, because only one of them centralizes power. > At this point they already have a consensus, they trust each other, they might as well just set up a centralized database run by a 3rd party that manages the system This is the critical point where I don't think the argument works. Firstly: they don't necessarily trust each other. They trust the system to work within the rules they have established. It simply doesn't follow from that that they should therefore be willing to trust a 3rd party. For what it's worth, this is why I'm interested to see how the block size situation in Bitcoin resolves itself. If it happens relatively smoothly, it's a strong point for the ability of consensus to respond to pressing needs. If it doesn't... well, I might have to reconsider my position.