You cannot live without fiat money, and there is no fiat money without bitcoin. You just need to have some coins in order to have fiat money.
What are you saying?
Bitcoin can exist without fiat currency. Only reason why people are trading fiat with bitcoin is because bitcoin is not yet completely mainstream. The discussion here is about the depreciative nature of fiat, and how they always end up being valueless. I completely agree with that, as you simply can't find any successful fiat currencies at holding value for the long term.
Bitcoin/gold/silver/other decentralised currencies can not only exist without fiat, it can also hold its value in the long term.