Oddbean new post about login | logout you're right Mike. The average fiat currency lifespan is under 30 years (UK pound is oldest at c.93 years. The Rai stones worked for centuries until an Irishman managed to apply better tech. to carve and ship the limestone lumps, thereby debasing the money. They even worked as money when they were on the seabed!
With all of that said, the dollar system is probably the strongest, most entrenched network in the history of humanity; it could have another 100 years. Let’s not underestimate its global dominance, liquidity, and influence.