All such protocols, even Bitcoin and friends, break under a sufficiently costly Sybil attack. The trick with cryptocurrency is to make the attack so expensive that it requires a highly economically irrational actor.
What are the thresholds here?
Doesn't that mean that an adversary using multiple identities would be able to do so? And therefore, some means of limiting the number of identities (through public key or prior trust) would still be desirable?
What am I missing? Is this mitigated through staking?
Sybil prevention is something that I wasn't taught at school and it concerns itself with creating the pre-requisites for consensus algorithm. Given the world population, how do we establish participant set for consensus while minimizing their chance to attack. Well, maybe by requiring them to waste record-breaking amounts of stupid compute.