It is an "economic theory" (to be magnanimous) whre maxing-out our credit card is great but it is utterly silent on how the credit-card debt can ever be repaid once our "credit limit" is hit.
The closest these debt zealots come to ever even considering "sustainability" is to tell us that as long as the growth of debt is at or below the level of economic growth that everything is fine. Translation? As long as we can make payments on this debt then everything is fine.
What happens when the cumulative interest payments on debt become unsustainable? The deadbeat debtor begins to borrow additional money just to pay interest on debt. This has the direct mathematical effect of transforming the speed at which debt (insolvency) rises from a mere geometric rate (compound interest) to an exponential rate (compounding the compound interest).
All exponential functions in economic systems come to a quick and gruesome end. In the case of the unsustainable debt-bubbles of Keynesian economics, the