[colinmhayes]

The empirical evidence that money supply increases don't necessarily cause infaltion is https://fred.stlouisfed.org/series/M2SL from 2009 to 2019. Money supply doubled and inflation was non-existent. Obviously this is an incredibly complex topic, but there was at least some reason to believe inflation wouldn't be as high as it has been. There are also many reasons beside money supply inflation for the rise in price inflation.

[shock-value]

The key phrase is of course "all else equal". A lot was going on in that decade that could (and is) argued to have been an opposing deflationary force. Worldwide demographics and productivity improvements, in particular. (On a separate note, much of that is or will be slowing/reversing in the coming years.)

To argue that an increase in money supply wouldn't lead to price inflation (again, all else equal) implies that the difference would just be hoarded indefinitely rather than used to buy anything, which seems unlikely just on the face of it.

[colinmhayes]

Sure, but all else wasn’t equal during covid, so I’m not sure that’s a fair addendum.

[shock-value]

I'm just arguing against this general idea that "increase in money supply doesn't cause price inflation". Which doesn't even really make sense because prices are measured in units of money. But the further implication, that Fed policy has no impact on prices, is just wrong to me and reflects some kind of misunderstanding.