It seems that this can go on indefinitely because we cannot envision the central banks losing control of interest rates, but absence of evidence is not evidence of absence. Believers in Modern Monetary Theory mistake this trend for a true principle. Central banks will remain active in controlling interest rates because the debt is so large that any spike in interest rates would be disastrous. We are stimulating a zombie economy reliant on low interest rates provided by a central government even more dependent on low interest rates.