Fiat will never die. BTC will one day unless it does something about the tx fees... People are greedy. Why pay a fee, to pay for something when there are other ways you can pay for that same item for free.

And don't get me started on the volatile confirmation times.. ::eye roll::

Why wait in some cases an hour to receive a payment, (the funds are spendable now anyway since you can technically transact unconfirmed btc) when you can receive the payment another way instantly? (Yes, I know about lightning obviously but it's not wide scale enough worldwide or even in the crypto/BTC community to count)