Pygmalion Effect vs Leadership

Have we been robbed of our leadership potential due to exposure to 'bad' teachers?

The pygmalion effect defines that "if teachers were led to expect enhanced performance from some children, then the children did indeed show that enhancement. In some cases such improvement was about twice that shown by other children in the same class. The pygmalion experiment was to support the hypothesis that reality can be influenced by the expectations of others. This influence can be beneficial as well as detrimental depending on which label an individual is assigned."

In hindsight, I tend to believe this behavioral correlation exist. But we might argue there are other influential factors such as environment. Obviously yes. But other than the parents, the single biggest influence on children, remains rooted on teachers.Comments?