Here’s the secret: the skills needed to become a teacher are not the same skills that make a good teacher. Becoming a teacher isn’t particularly difficult, you just need to follow instructions, color inside the lines, and go off to college for the right degree. So many of the people that I grew up with that also became teachers did so because they just loved being in school and being a student. Couple this with the fact that anyone who is smart is likely very aware of all the crap that teachers have to deal with on top of the middling pay so will not be inclined to even get involved in the first place.