Well, I agree with you and Jordan; the point I'm making is not just about teachers and education. Let me put it more broadly: imagine we have publicly funded organizations structured to fulfill a particular public mission (say, health care--I can dream, can't I?). To effectively serve the public good (say, providing health care services to maintain public health), we need to prudently use the resources to fulfill that goal. If we waste resources (e.g., we follow Michael's exhortation to "slack off!"), we're not contributing to the common good.
"Prudently using resources" in a socialist organization consists of many elements. Sure, no glitzy management meetings in Las Vegas, no overpriced consultants hawking magical management fairy dust, etc. But also: the people carrying out particular jobs do their jobs competently. For instance, if a doctor does not competently provide patient care, he should go through training and professional development to improve his performance, and he should be replaced if his performance does not improve. If we do not hold people to rudimentary standards of professional competence in public organizations, we undermine public welfare.
Perhaps the wariness about judging professional competence in teachers and other professionals is based on a more nuanced definition of "competence" than I'm assuming. I'm not saying we need to make fine-grained decisions between okay and great; we need to make a gross distinction between carrying out the necessary job duties and not carrying out the job duties. As long as the job is well defined, it is relatively easy to make this gross distinction (the people in any work group make this distinction informally all the time!).
Miles