The graph shows that, after 60 years, the private economy is 5 times its 1950 size. But state and local governments are spending almost 13 times as much as they did in 1950. “This is like a household whose income has grown five-fold over a period of time,” Mitchell reports. “That’s great news. But, unfortunately, their spending habits have grown 13-fold. This divergence is unsustainable.
Perhaps Mitchell is correct and this trajectory is unsustainable. Though, if we would have said that in 1975 when public spending was double that of private GDP (with respect to their 1950 levels) we would have spoken at least 35 years too soon. Being unsustainable is no reason for something not to be sustained.