That seems like a leap to me. I bet there's plenty of people who could take over that life and rough set of preferences and do a better job of being happy.
If I say that some people would be happier in some kind of impossible to reach theoretical, that's not a good thing, is it?
And the person you were talking to didn't even say they were happy! They just said they're the best at some combination of things. Even assuming they are happy, they're probably not near the top of the happiness charts. "best at making yourself happy" looks to me like a completely unfounded guess/hope.
this is a good thing.