>This game of convincing people that your fork is the true fork is exactly what stake-grinding is
Stake grinding is something else, in coins like NXT the producer of the next block was set by the seed based on the previous block, so it was possible to bruteforce blocks until you were also the next generator.
>The article argues that the act of convincing you is, itself, a form of PoW.
He makes a much stronger claim that resources spent on that (+ staking) are equal to revenue. There's an additional assumption in the article: he writes about marginal cost and revenue, but what he actually assumes is a system where average cost is equal to marginal cost, as it is in PoW under perfect competition. It's even equated explicitly in "“Rent” always forces production costs (MC) to always equal sale prices (MR)". He starts from the assumption that PoS uses exactly same resources as PoW and then shows it's true based on the assumption.
>Given a choice, and no a priori knowledge, which history of the PoS chain is the true history? What would convince you that one is legitimate, and the other is not?
What does 'true' and 'legitimate' mean here? The whole point is to interact with other people, so naturally I'm going to use the same network that people I want to interact with use. Same whether it's PoW or PoS - no real difference between choosing forks from some block height vs choosing networks with completely different genesis blocks and names.
Once the network is chosen a node has to follow it. The question of 'how long it's safe to be offline to reproduce the behavior of being online all the time' has a complex answer of percentage of slashed stake if two conflicting histories exist. Currently I think it's about 16% for one month, which is about $2B.
>Without no 3rd party way to verify if that actually happened, you could go around trying to bribe people to accept that your subsequent transactions on this fork are the chain's "true" transactions.
PoW doesn't change anything here, it's an arbitrary fork like any other. People that ended up with coins from mining can receive coins on your fork too, made with a much smaller mining difficulty. Mining cost is irrelevant because that's destroyed wealth - nobody ends up with it.
The reason it won't happen in reality is because of network effects - even if you have external wealth able to pay enough at once to everyone that has to be paid, no single person wants to be left alone on a new fork - they would all have to move at once.