Not that I need some attention, but I would like to have answers to my questions.
I would have thought that they would be self evident by now.
Let me restate my question. Why should a node 100000 blocks ahead accept a blockchain re-organisation?
Because the network follows a longest chain is valid rule? If it doesn't then you are relying on a node knowing that an alternate chain came "later" and not all nodes will know that. As I already pointed out up thread imagine you are a new node, you connect to the network and receive two competing chains A & B. A is longer. Which chain do you use? If you use A and other nodes use B that is a problem (isolation attack and network fork due to non deterministic chain selection). If they are choosing B over A because they "saw it first" there is no way for you to confirm that or even know that.
Still it doesn't need to be 10,000 blocks. A 51% attack can be accomplished with a reorg of any length.
Um, well no. I can't mine using computing power I no longer have (but did have at one point in the past).
Our mining rigs destroy themselves? I doubt it.
If I have a rig (or more accurately a massive mining farm that is a majority of the hashing power) I have incurred a cost and I am taking a risk by executing an attack. The difference with PoS is that an attack can be executed without cost or risk. That would only be true for PoW if I could build a farm, then sell it, and then somehow execute an attack after the sale with the farm I don't have. It was tongue in cheek to show that since PoW can't be exploited by history, I can't perform an attack with no cost of risk
However, the huge advantage of PoS is: the network controls the consensus power and the network can punish the bad guys. I would call this the PoW problem as the consensus power can easily be introduced from outside without any control whatsoever.
The network can't punish the bad guy. The whole point is that PoS, the bad guy can attack without cost or risk. How exactly does a PoS punish an anonymous entity who no longer has anything at risk and can attack you with no cost. If that were true that checkpoints wouldn't be needed. There is no PoW "problem". There is a limitation that both PoS and PoW share and that is the security model only works if the attacker has less than half of the resource. An attacker can buy computing power and an attacker can buy a stake neither are closed systems.