If the job prospects of history majors are teacher and cab driver, then it's not very attractive to many people for good reason. History is important, historians are important, but not everyone needs to study it. The skills only have limited demands on the job market and its dangerous to tell people to study history if they have meek prospects, especially in a place like the US where colleges aren't tuition free.
I realize that this is likely what you intended to communicate, but I would differentiate between the need to study a subject and the need to specialize in it as a career path. I agree that not everyone needs to become a historian but I think that everyone needs to study history.
