Teacher requirements vary by state.. but not a single state requires a teacher to have a master's degree[0]. Some states require a masters to get certain certifications or to teach at a certain level, but other states dont require one for anything. Not to mention, charter schools in some states aren't required to hire teachers who are even licensed or meet any of the requirements of a teacher:
0. https://thebestschools.org/resources/teaching-requirements-b...
There is no federal teacher licensing standard, and state standards vary (and only apply to public school teachers, IIRC). In several states, the only educational requirement is a bachelor's degree. [1] This educational requirement might be coupled with required teaching experience, but this experience can be gained by teaching in a private school, where such requirements do not apply. And none of these experiential requirements establish a baseline for excellence — they just measure based on "time served".
It is simply false to assume that all teachers are "experts" to whom parents (who may have many more years of education, not that formal education is the touchstone), should defer.
1: https://www.axios.com/2017/12/15/8-states-that-made-it-easie...
Teachers in the US are required to have a Master’s level education and multiple months of student teaching in order to be certified to teach. Yes, there are many kids in the classroom. Yes, your kid isn’t going to get the same type of 1 on 1 attention you can give them at home. However, work in conjunction with the experts, don’t presume you know better by default.