Simple ignorance. Unfamiliarity. Fear. Laziness. Aversion to working with 'wastes'. Information assymetry. Myths, disinformation, risk aversion, a Zeitgeist of apathy, disbelief, defeatism, lack of trust, lack of experimentation, systemic patron-client discouragement, bad public policy, lack of incentives, withholding of key information motivated by a desire for profit and personal gain. All psychological, none technological or material.
In other words "if it is so damn good, and so damn easy, why isn't everybody doing it?"