Thank you bitcoin for solving the byzantine generals problem
Bitcoin does not solve Byzantine generals as I explained 3+ years ago in the huge 11 page thread below. Tons of people posted in it from Anonymint, to Come from Beyond, Smooth, etc:
https://bitcointalksearch.org/topic/satoshi-didnt-solve-the-byzantine-generals-problem-1183043 you can't solve byzantine generals problem with a probabilistic model unless you've first solved sybil with a probabilistic model and Bitcoin doesn't do that
because there's no way of telling if all pools are owned by the same person, then it's not collusion or 51% attack, it's a sybil attack
since the essence of the byzantine generals problem is sybil attack, dealing with sybil comes first in the hierarchy before byzantine generals is discussed at all
The Byzantine problem deals with a minority of actors or signal throwing off the consensus of the system or majority. If you can't determine how many actors even exist in the first place, you're probably always going to lose this test. This fact might give credence to some form of deterministic block validators model, but that's outside the scope of this post.
The part where the biggest disagreement will come from, is that people will claim there are incentives against a big hash man owning several pools that make up the majority of hash rate. This is obviously false. There are no incentives against him taking this course of action, since he can do so in secrecy, there are only incentives against him making double spends. I would argue that even if he isn't double spending the security model is broken. If you accept this security model, there's no reason to not accept a security model of one guy always having 90% hashrate out in the open (not trustless, they can double spend at any time).
Since bitcoin was released, there are ORDERS OF MAGNITUDE more people working on digital currency than pre-bitcoin. The fact that after two billion altcoins and all these new people working on them and STILL there is not a single decentralized coin tells you all you need to know. From a conceptual point, I can tell you it's 100% impossible to create a decentralized digital currency. And all these failed projects that have had billions poured into them and came up with absolutely nothing just reinforces that fact.
Conceptually, I can also tell you Come from Beyond with the only half ass attempt so far at unprofitable PoW is the best theoretical path towards one, but unprofitable PoW is an unworkable solution due to requiring artificial convergence. When the only valid conceptual path forward (unprofitable PoW) is impossible to work, it's game over.