Altcoins precisely prove that finding rules everyone would like is impossible (or close enough). So suppose you'll settle for a majority. How will you persuade people? If there's a lot at stake, and the system is complex enough, you can't expect everyone to be well versed in the details, so you'll need professional politicians and a representative democracy.

I think you're reading too much into what cryptocurrency is. It is simply a somewhat-elegant solution to the problem of building a decentralized, digital cash. That's it. It doesn't try to find new ways to run the economy, although some of its supporters do because that's their politics. It doesn't even prove that this is, indeed, a serious practical problem, but that's what some of its supporters believe.

What you call fallible, others might call "free". For example, I would like to give the government the freedom to quickly devalue the currency in a time of a job crisis. What you're proposing either takes away that freedom altogether, or places a serious bureaucratic burden on the process, so that it might not be feasible. You're basically suggesting a system with an unbreakable bureaucracy which is just about the only thing worse than the current situation. There will be no one to talk to – hey, it's just the algorithm – other than somehow convince a majority of anonymous account holders, with whom you can't bargain because they're unlikely to reveal their true interests.

The difference between us, I think, is this: we both don't like politicians plutocrats and corporations. But you believe that they can be eliminated through some elusive algorithm, while I think society contains within it endless cycles of many concurrent power struggles, and each of us must find their place in it, and fight for the values they believe in, knowing full well that the fight is never truly over.