“How many students paid tens of thousands of dollars for master’s degrees in teaching”
Nobody.
If you have a Master’s in Education you can always find a job.
It may not be where you want to work and you may not ever get rich but teacher’s can always find work because there are always vacancies somewhere.
The “credentialed” people that can’t find work are the ones with degrees in fields where the only jobs are professors in that field.
A job as a teacher’s assistant.
I bet you can get a job as a real estate agent with your Trump certification and earn as much.