QE without public debt sterilization is going to appear as the costliest macroeconomic mistake of the early 21st century.

Disagree, fairly strongly. In 2008, four trillion dollars evaporated. In order to keep the economy from completely crashing, the Fed created $4T using QE and such tricks. The result was 15 years of flat. No inflation for 15 years. If inflation shows up a decade and a half later, that probably wasn't the fault of how QE was done.