Some are; some aren’t.
And some aren't worth keeping in the position - except they are anchored there because of tenure.
Also factor in that they have summers off and only 180 workdays!
Some are; some aren’t.
There are a few exceptions, but ...
Do away with public schools, provide vouchers to parents, let parents spend them on competing schools and teachers in the free market along with their own money to the extent they want special teachers and programs, and the answer will be NO.
Until then, given the power of the unions and the dead weight and inefficiency in the civil service, the answer is and always will be YES.
Virtually all are. A degree in education erodes marketable skills; it doesn’t add to them. Today most are in teaching because they would be unable to find indoor work with no heavy lifting anywhere else.