I do not think bitcoin will be able to save the fiat economy. First and foremost because bitcoin is not connected to the fiat economy at all. It may have been a point of comparison but that's as far as connection goes between these two things. If it were to collapse, bitcoin will be the go to of the common people, and those who adopted it earlier will have a considerable headstart compared to those who FOMOed.
The nature of Bitcoin as a financial asset has attracted the interest of many people and created potential financial losses. Although the line between money and financial assets is not clear, people's actions often reveal the role that these assets play in the economy. These days, the joy around Bitcoin is buying it as a financial investment, not using it as money to buy goods and services.
I think, Bitcoin is "not a stable store of value, and is not a legal tender"; in his judgment, Bitcoin "is a highly speculative asset. Of course, it is very risky if our assets put everything in bitcoin, but it is different if only partially because it is not impossible that bitcoin can be one of the income that can change our finances.