Harmonisation of fiat and crypto will never happen. Also it is wrong to state that fiat will die anytime. Thats wrong terminology. Money or fiat money precisely will never die, it will just get valued more or may be it will get devalued with the time. Only these two things can happen with it and this is the right way to put it up. Cyrpto currencies are created under certain limitations and they will never ever replace the fiat in anytime soon. At least not for the next decade for sure because they are incapable of doing so. With the crypto being so tiny it can not fulfil the needs of real world.