People possessing the greatest minds of all time, like Albert Einstein, would not be permitted to teach at K-12 public schools because they lack(ed) an "education" degree. That is, they didn't spend thousand of dollars propping up a system of "teaching teachers" that has become a system of entrenched, unionized bureaucracy.
I've taught at the university level, tutor students of all ages and substitute at the K-12 level but am not "allowed" to teach full time in the public K-12 system because, you guessed it, I haven't shelled out thousands of dollars to obtain an "education" degree that allegedly demonstrates that I have received the proper education to teach.
Because, you know, actually teaching isn't proof of anything!
Hat tip:
John Stossel.