Fiat money is a bubble but the probability of bursting and bubble bursting rate is very low. Money FIAT is a unit representing the economy of a country. The country's economic sectors and the type of assets it owns are guaranteed for the currency they issue. It could be called that. If the economy develops stably, the political situation is stable and they have good monetary management measures, the bubble market will not break. They may be timeless but regulated. Like some ICO projects that sell airdrops. At first the airdrop will be diluted into the market but then they will rise again.
Crypto currencies are mined or released more fragile because the individuals behind them are a group of people, a startup company. They may cancel the project or they will resell the project to another individual or company. And the FIAT money represents a nation and they seek a way for their country to exist.