Can we just make QEX a permanent part of the US economy? As long as inflation isn't a problem, is there a downside to just perpetually printing money that is essentially turned into instantly rising corporate valuations? Seems like it's only a problem if they shut it off, but that's true of most government programs.
I think the reason they really don't want to is because inflation is a multi-fauceted problem.
For example, if they keep printing until inflation does start edging upward, then eventually anyone the US government already owes debt to starts to see a very real valuation decrease in their holdings.
Now, investors/other governments do not operate on the concept of "so long as dollar inflation is down right now my holdings are still good". They act upon the, "What did they do right now which might impact me for the next 5-10-15 years?"
If the US comes out and announces that we will just keep on printing so long as people keep hoarding dollars, that alone can trigger a flush of dollar debt so that the investor avoids getting caught in the eventual future pinch of debt eroding with inflation.
And that flush would also impact current inflation, and a bit of self-fulfilling prophecy happens and people panic, and so on.
On a related note, I believe the Feds' current stance on relieving itself from its QE collected assets is to allow the debt to mature naturally rather than reselling it on the secondary market. If they try to sell their substantial amount of debt assets to quickly, it floods the market which can again trigger an inflation slide if the economy can't proportionally keep up with the transfer of money.
I don't think there is a lot of historical situations with a similar enough setup in globalized debt ownership with multiple, inter-connected fiat currency systems all being used at once to really give us a good idea on what would happen. And of course, this is all
theoretical smoke. The actual market reaction can turn the "theory" all up on its head and leave everyone wondering wtf happened, and then why, and then "Oh! Why didn't i obviously see that coming?".