> schoolteachers have at least two university degrees and consequently have expertise in their profession

Utter fallacy. Expertise in teaching requires training, experience and/or natural talent.

I'm curious what you consider "training", and how this would be different than a vocation-specific university degree? Which typically also includes supervised real-world teaching experience?

I'm intrigued as to what you think one studies as part of a Postgraduate Certificate in Education or a Masters in Education.