No one - who's talking at least - seems to understand what's going on with this. It's uncharted territory in a world economic system way more complex than when text books were written.
I have to think fundamental reality must catch up sooner or later, possibly unravelling in a sudden crash.
Then again, I do not understand this!
Conventional explanations include "price stickiness": wages and prices don't change overnight, they have to be deliberately changed by individuals in the market. And the more technical "transmission mechanism": just as an automatic transmission doesn't immediately convert faster engine RPM into faster road speed, there is substantial lag in the mechanisms by which money production affects prices.
The reverse process was seen round about the introduction of the Brazilian "Real". People had become used to inflation and re-negotiating prices regularly. Swapping out the name of the currency helped reset that in the minds of the public. https://en.wikipedia.org/wiki/Plano_Real
One of the more convincing ideas is that, because fiscal policy is either conservative or only expansionary for high earners, monetary expansion doesn't affect most consumption prices and only affects assets. e.g. house prices and the stock market.
The moment people think a currency is shaky, they get their money out of it and into something else. That leads to a huge oversupply of that currency in exchange markets, crushing exchange rates, and making the prophecy of inflation self-fulfilling. Much like borrowing, the moment people think you need to print money to survive is the moment everything goes to hell.
That being said, I think the fed's policy has been pretty reasonable. Europe and Japan have been more aggressive with monetary policy than the U.S. over the last decade, making the dollar very strong and worsening the trade imbalance.
Secondly, people get confused between extension of credit and money printing. For that you want the separate measure "M2".
Thirdly, the real lesson of the hyperinflation crises of Germany, Zimbabwe, Argentina etc. is that you can't print oil, gold, or the foreign currency needed to buy them. Germany was paying a huge amount of reparations to France (which would be where the family silver ended up - 20 billion goldmarks was paid, which had to come from somewhere).
The United States is in a hugely privileged position. It has enough domestic oil and food production for its needs. The gold standard is no longer relevant. Inflation and interest rates remain low.
If you imagine a dial with a yellow warning at "8" and a warning redline at "9", the US is currently arguing over whether turning it from 1 to 2 is going to be the end of the world. The limit does exist, but it's a long way away.