Saying that fiat money is some kind of a bubble is not a right thing, because in fact it is not. That bubble would have been popped years ago, and as we can see, it still holds for now.
The regular cash is something that too many people rely on, to think that there is any chance (for now) that we will have something different instead of paper money.

After all, what do you want to see as a replacement for fiat, do you have any suggestions? If you are wondering that bitcoin has any chance to overcome the fiat, then you are wrong. Blockchain network is not ready at all to maintain under such a massive traffic, and the another issue is that the fees currently are exceeding the reasonable amount of money spend for commison. You cannot buy some cheap things ( e.g matchsticks or cans with drinks ) because the price would increase dramatically, because of a insanely high fee payed on every transaction.