I used to agree with this but after watching my fiancée teach for the last few years, I actually think most people are pretty bad teachers, including many teachers. 

Degrees don’t fix things but we underestimate how hard it is to effectively teach a child (even harder a classroom of 20+ kids w unique needs)

(didn't mean to insinuate she's a bad teacher - I actually think she's the best teacher in most environments she's worked in, and what people think of when they think of a good teacher, but there are a lot of underperformers)