I'm going to provide one more example and I'm approaching this from a philosophical point of view, so I would appreciate it if people take the same stance as it being a philosophical debate.
You have 2 women: Sally and Jane.
Sally and Jane both start a rigorous course in university together. Sally is pressured by family and society to pursue a healthcare degree. Jane is pressured to do the same.
Sally and Jane are out on placements. They realise that the workforce they are with are stressed, understaffed, and at complete risk of being blamed/sued for cost saving policies by management. There is also a continuous risk of catching an illness because insufficient personal protection is provided (again another cost saving measure).
Sally keeps trudging along because she can't back out now and face what people would say if she were to quit.
Jane says "Fuck that" and finds a billionaire that marries her without a prenuptial agreement. She never has to work a day for the rest of her life.
Sally graduates with her formal education but cries on the way to work everyday because she hates it, her anxiety grows more as she fears the fateful day when something goes wrong, and she is blamed for it.
Now I'm not saying that Jane IS smarter than Sally. I'm saying that they have different ambitions and it's impossible to say who is smarter than the other. It's subjective. Some people will say Sally is smarter and some people will say Jane is smarter. My point is that people can be intelligent and make different life choices than pursuing formal education.
Formal education does equal a decrease in fertility.
Intelligence does not equal formal education.