If you object to the word "successful," then just replace it with something else. His meaning is the same as in evolutionary biology: it out-competes its peers and continues to exist. He does not mean to imply that its good or that the people who comprise the culture are happy.
By analogy, I would claim that sharks are successful. By the standard above, they clearly are: they've continued to exist and out-competed peer species for millions of years. But I'm making an objective claim only, not a value judgement on whether or not this is good.
By analogy, I would claim that sharks are successful. By the standard above, they clearly are: they've continued to exist and out-competed peer species for millions of years. But I'm making an objective claim only, not a value judgement on whether or not this is good.