Actually I highly doubt that. Fiat currencies are backed by the government and is controlled by them. They tend to regulate the money by manipulating supply and other economical factors.

Even with wars or any other events that could turn fiat currencies into a spiral I don’t think it will get as bad as not being stable and being similar to memecoins. I am sure that even if that happens the government will try to solve it and  regulate some of their policies to make this hypothetical phenomenon stop.