Accounting for equity and non-liquid deposits (which I don't do in lower division courses), the gap equals loans minus equity minus non-liquid deposits. I call this quantity "net financing." Read more in my paper forthcoming in the Journal of Economics Teaching: osf.io/preprints/so...

Using a simplified balance sheet for the banking industry (meaning equity = 0 and all deposits are liquid enough to count as money) then the balance sheet identity implies that reserves (R) plus loans (L) equal deposits (D). This means the gap equals L, so the diagram illustrates money creation.

How can the ratio of the money supply to the monetary base be dead? What really died is the assumption that the money multiplier is constant. The ratio remains a useful economic measure. osf.io/preprints/so...

During the financial crisis the multiplier fell drastically as reserves were pumped in while lending did not increase proportionally. Of course you can see something similar, but less drastic, during the COVID recession as well.