The change is that we have socially and psychologically extended childhood. So a 17 year old girl today represents someone much less self-actualized than a 17

The change is that we have socially and psychologically extended childhood. So a 17 year old girl today represents someone much less self-actualized than a 17 year old lady 200 years ago. But the result (for all persons) is a more skilled, highly specialized, more brainy vs. brawny (behaviorally) work force.