He who can - does
He who can't - teaches
He who can't teach - teaches teachers
He who can't teach teachers - does educational research

This is exactly the kind of smartasrse, sound bite, crap that leads to the mess we have in public education and in fact every aspect of our political lives at the moment. The constant changes in educational policy come not from research but from a society that finds it easier to slag off other peoples efforts than to do the research to find what really works.