read the paper PeterR and Justus referenced.
the "truth" in a POW system is determined by the objective laws of thermodynamics which are fundamental laws that exist outside the POW system. it cannot be gamed by the stakeholders.
the "truth" in a POS system is not determined by any such laws outside its own system. it is self referencing, aka an echo chamber, of whatever the stakeholders "want" to be the truth, whether objective or not. it can be gamed by the stakeholders, if they all agree.
But why would they all agree when doing so would destroy the integrity of their stake? As we saw recently getting them to agree on such a change is near impossible and will only get more difficult as the system gets bigger any many forgers are companies that have their businesses built on top of the system.
Are you saying that AI will never be possible? Because that is a self referencing system.
POW is a better and more fair method of distributing new coins, but that is all.
Once bitcoin is widely distributed and the majority of block rewards comes from fees and not minting, then switching to a POS system seems fine.
Both systems are identical on how security is created, they only differ in who gets to vote. In POW votes are allocated based on how much electricity one consumes (assuming everyone has access to the same technology which will be true after ASICs settle down). In POS votes are allocated based on the number of coins held. The concepts of a voting based system are the same.
BTW bitcoin already did a rollback in March 2013, yes it was to correct a bug but the devs looked at the situation and asked miners to abandon the longest chain and build a shorter one. This is possible with POW too... Bitcoin is still based on the laws of men (not thermodynamics), its just that bitcoin aligns the interests of the "voters" in a way to create a rules based system.
