[dragonwriter]

> The money multiplier is not some foundational macroeconomic article of faith, it's a pedagogical tool to illustrate how leverage can expand the money supply beyond the monetary base to first year undergrads

Particularly, it's a tool for estimating a limit of an effect in a particular idealized policy circumstance and with other simplifying assumptions.

The simplifications don't represent real world conditions, so the computation is of little real-world relevance though the effect is.

Much of a first-year physics text will be simplifications that apply in idealized conditions that are broadly similar, IME.