Here is the problem. Teachers in America compare themselves to professionals, but their test scores are below the average for college educated people generally: https://www.brookings.edu/blog/brown-center-chalkboard/2017/.... Now 40% of college graduates don’t even get a job that requires a college degree. Disproportionately, those are people with lower aptitude scores. Teachers as a group are right on the borderline above those folks.
Teacher salaries are not low compared to jobs typically held by people with similar test scores—especially when you account for degree-required jobs that pay a premium for mathematical aptitude (accounting, engineering), or dealing with blood and body parts (nursing).