Bitcoin have the big chance to replace fiat. Becouse people in some countries were change their money in to bitcoin to save their wealth when their fiat price is fall against USD. Those country need to import logistic that they have to pay with USD. So I think people will prefer like to use bitcoin than fiat.
Ha! You didn't know Bitcoin is already a fiat currency in digital world and the real world too but I admit that some country not accepting Bitcoin they banned it and illegal to them.