"The proliferation of fiat may very well have been the last nail in the coffin but at best capitalism exacerbated it but I suspect it is actually responsible for pushing us in the coffin in the first place."
You are correct, fiat was/is the nail in the coffin of capitalism - it did NOT exacerbate it, but ruined it (history shows it always does) - we have been straying from capitalism for decades - over half a century. Some would say since the income tax over 100 years ago. World War solidified fiat.
Capitalism is just the REAL exchange of human energy - something you have that I want and something I have that you want. A 'currency' is needed because what you want is not always what I have - so it allows our ENERGY to be translated to a medium of exchange. IF that medium of echange does NOT represent real human energy (which #Bitcoin does and Gold did it okay but was ALWAYS corrupted) than capitalism dies.
Hate to see people get mislead on the Capitalism issue - remember the Communists (collectivist) have been hammering on real capitalism for centuries. Why? So a few can control the narrative/people/production/power.