Proof of stake entrenches a group of rent seekers in perpetuity, without the need to do anything external, or anything whatsoever. The risk of mining is quite high as we've seen the past few years and there is no singular entity that has dominated Bitcoin mining for more than 3-4 years. Furthermore even when Bitcoin was dominated by Bitmain and a few other miners predominantly in Asia, they were unable to use their mining power to influence Bitcoin.
So the argument comes down to Bitcoin depending on external factors that are quite risky and requires constant upkeep and innovation in order to maintain ones position in the ecosystem, versus proof of stake where absolutely nothing is needed to maintain one's position.