The fraction of people out of the total population that will actually want (need?) a PhD in math, physics, or other related fields doesn't really support your s

The fraction of people out of the total population that will actually want (need?) a PhD in math, physics, or other related fields doesn't really support your statement. Also, I know plenty of parents who don't have specific career goals in mind for their children, who support their children following their own calling towards a particular profession.