That's not how it works. Hashpower decides the canonical chain, not the rules of the system. Hashpower makes sure that the blockchain can't be rewritten. Hashpower can't change the rules of the system, because those blocks would be invalid and rejected by the network.
There's no consensus needed on which rules to use. Everyone can use whichever rules they want, by using different versions of the software. Different rules define a different currency, like euro or dollar. Using the best currency with the best rules is just a game theoretic focal point. Everyone chooses to use the best version of the software, because they assume that everyone else does so too, even in the absence of communication. There is no "correct, current" software in Bitcoin, because it would be a single point of failure.
There's no objective protection against long-range attacks in PoS, because there's no hashpower to prove the canonical chain. It requires the provider of the "correct, current" software to decide which chain is the right one.
>>Hashpower decides the canonical chain, not the rules of the system.
No, hash power and the rules decide it. If you have invalid signatures in your blocks, it doesn't matter how much hashpower your fork has, it won't be accepted as canonical by other forks.
There's no consensus needed on which rules to use. Everyone can use whichever rules they want, by using different versions of the software. Different rules define a different currency, like euro or dollar. Using the best currency with the best rules is just a game theoretic focal point. Everyone chooses to use the best version of the software, because they assume that everyone else does so too, even in the absence of communication. There is no "correct, current" software in Bitcoin, because it would be a single point of failure.
There's no objective protection against long-range attacks in PoS, because there's no hashpower to prove the canonical chain. It requires the provider of the "correct, current" software to decide which chain is the right one.