I think the author presents his points from strongest to weakest.

People have different priorities in life. Just how much someone cares about career, financial, social success really feeds into how they'd weigh these points. I would say the author wants children, but desires money and success more.

The point about 'energetic 70 year olds' is cherry picking and really quite weak. Many, if not most, people experience serious physical decline beginning in their late 30s and certainly by the 40s - even with some attention to diet and exercise. I certainly have.