There are lots of careers in education besides teaching. Some colleges do a better job than others getting students exposed to these careers- strategy roles in education reform, finance, marketing and general management roles for ed publishing companies, all kinds of jobs in tech for companies developing new applications for school systems, both learning technology and back office. And roles in educational administration- from school principal on up to governor appointee level jobs in education policy and management in each state.
I wouldn’t tell a 17 year old to set his or her sights so low as to assume that if the current goal is teaching 4th grade language arts, that this is the ONLY career aspiration this kid will have going forward. Some graduate programs exist to churn out students who meet that state’s requirements for K-12 teaching. Others have a more robust curriculum in educational policy, disruptive reform and technology, etc.
I don’t think teaching is a one size fits all career.