There have been countless falsehoods about language foisted on unsuspecting students over the centuries and these myths have taken on an aura of truthiness.
Read this, it'll help you see what's really been wrong with English teaching.
Consider the possibility that English grammar has been misanalysed for centuries because of grammariansí accepting fundamentally flawed assumptions about grammar and, not least, because of a flawed view of the history of English; and that these failings have resulted in a huge disconnect between English grammars and the genius of the English that really exists among educated native-speakers. The development of the information age and of English as a world language means that such lapses have even greater negative import than formerly. But what is available on the shelves has fallen into sufficient discredit for grammar to have forfeited its place in the curriculum, unrespected and little heeded by the brighter students.
HOW GRAMMARS OF ENGLISH HAVE MISSED THE BOAT
THERE'S BEEN MORE FLUMMOXING THAN MEETS THE EYE
by Charles-James N. Bailey