Often only investment and export are named to drive economies. Those who dare to talk about consume and the middle class are socialists. China and Germany are successful with this model but in the end it can not work for everyone nor forever.
Comparing apples to oranges. Neglecting the inherent problems of the field. Physics and Economics are fundamentally different. In physics the last 50 years have actually not brought about any big results.
When it is so simple: If there is too much debt, there is too much credit. In order to reduce one we must reduce the other. Simply raise the inheritance tax for 50 years and the debt and demand problem is solved.