Ya, I’m concluding that “money” is now mostly debt. Perhaps oversimplifying, seems the Federal Reserve creates money by the math $0 = $1 + -$1. They start with nothing, loan a dollar, and note that someone owes them a dollar. So yes, once all the accounts get balanced out (trillions of dollars) it all returns to $0.
Of course the details are more complex, injecting real M0 money (physical currency) and other real value into the system, but on the whole a dollar (the virtual stuff we claim to have, not the paper & coin we mostly don’t) is a promise someone somewhere will pass a dollar back thru the vast chain of debt and it all returns to what’s left of M0. Of course, settling up won’t happen - it all collapses at some point, like the loan guarantee debacle when a bump made everyone realize they were insulting themselves with nothing.
Physical currency is nothing more than a representation of Treasury bills, notes, and bonds.
If that debt were paid off then currency would disappear.