You are missing the point crypto is an intermediate system its not the end all be all its just there to co exist with fiat. till the entire population agrees to a new sort of system. crypto is not about destroying the old system its about adding value to it., so there will be no depletion of value for fiat. around 2025 is when you will see a crypto boom though where it will explore and grow very fast. but in the end its just a system that is meant to bring greater freedom and will last lets say 20-30 years before a new better one comes about.