Large, pluralistic societies create a new kind of natural-selective environment that pushes cultures towards greater fitness in their niches or rewards cultures

Large, pluralistic societies create a new kind of natural-selective environment that pushes cultures towards greater fitness in their niches or rewards cultures that expand into or create new niches. You definitely can't expect all cultures to behave the same way and exist in all niches. See e.g. the enormous propensity of Mormons towards dentistry - "be a dentist" is not a valid universal cultural attribute, but can be adaptive for a small group. There are many routes to success.