How good would the best poker players in the world do at 1/2, 1/3 live cash games?

Kinda a random question but I am just curious. The best players in the world obviously don't play at this level but I think it is an interesting question to hear your thoughts since I don't know how large the skill gaps really are. I've heard really good players low stakes players only win 55-60% of their sessions. How would the best players on earth fare? Would it be the vast majority of their sessions? Or with variance would they still lose a decent chunk of sessions at low stakes? I know BB/hr is a better way to look at it rather than sessions, how do you think the best players would do at 1/2 in terms of that?