Everyone with half a mind started shorting dollars at a certain point, whatever the asset or commodity of choice. First principle: every unit in a credit system is credit owed to someone. Which means that every unit is owed with interest, which means the interest needs to be newly introduced into the system to maintain the debt.
Interest is the natural growth rate of fiat. The extra money to pay the interest does not exist yet → it must be created by someone else taking on new debt. This is exponential decay, it is exponential because a percentage, no matter what the percentage is, is added every year to service the debt.
This exponential property of fiat is mathematically absolute, totally glossed over by most economists, and only requires you to buy some #bitcoin in case it catches on.