[zodiac]

I agree with your 3rd, 4th, and 5th sentences, but not with your 1st and 2nd. Assuming a large number of independent validators, the Nash equilibrium is close to "there is no equivocation, hence no slashable evidence, hence no incentive to run a slasher node". (Remember that Nash equilibrium implicitly assumes that agents are not allowed to cooperate with each other). Suppose some fraction of the validators are deviating from this equilibrium by doing lots of equivocation, now there is an incentive to run a slasher node. So what this modelling suggests is that in the real world, we can have a small number of slashers and a large number of validators, and the security comes from the fact that anyone could be a slasher (it's OK that the number of people who actually are is small). But we cannot conclude that "it's OK to have a small number of validators, as long as anyone can be a validator".

[spywaregorilla]

I don't really agree but sure, however this counterpoint retracts the original premise, that the slashers are centralized. Something can be done with a small number of people and still be decentralized.