The reason is simple: if you have the treasury mint a $1T coin and give it to me, then I throw it in a vault, and do not spend it then prices do not change. As such, the Austrian model is obviously incomplete as it does not take into account what happens to that supply.
You can see this play out in the macro. Since 1980 the M2 supply has increased 12X but prices are about 3X higher.
Money in a vault has zero velocity, money being spent dozens of times a day has a very high velocity, most situations lie between, we need a meaningful way of discussing this that "monetary supply" does not capture.
There is a common idea that high monetary velocity (GDP divided by broad money supply) is needed for inflation. However, the data show that this is not the case.This system remains at equilibrium because supply went up, and velocity went down leading to neutral price action.
It analogizes this graph: https://fred.stlouisfed.org/series/PSAVERT
As your access to supply increases, your demand for more monetary units decreases. As your demand for monetary units falls below your demand for other goods and services you want in life, you spend some of it.
This is how markets function, right? This is why bubbles pop for example, eventually holders of an asset reach a price where they want to take some off the table.
"Everyone has a price."