Yes. History shows that low income adherents to a faith freely give most if not all of their surplus income (to the church).
This is a sustainable model for a religious organization when the membership is a growth phase. And, when the culture of the organization encourages personal growth. Wealth flows 'uphill' in religion.
Organizations (religious or otherwise) that give back to their community develop strong local support systems. Jehovah's Witnesses - as a group and often as individuals - do not 'invest' in personal development, financial growth, social programs or crisis/dependency counseling.