It's funny that this is a question when every college STEM class is taught by people who have degrees that have absolutely nothing to do with being able to teach effectively.
If you were good at teaching STEM, I think you could probably work nearby in a STEM job for more money.
I've been multiple places were the teachers in high-mobility fields were bad because anyone good at them could move up easily. takes just one bad interaction with a superior or nagging from a spouse and poof.
This doesn't apply to people who love teaching, they're in it for different motivations.