You shouldn't worry about this. Cryptocurrency will enter our world for more than one generation. Now only a few percent of the world's population have cryptocurrency wallets and are engaged in cryptocurrency. It is generally accepted that the generation of people changes every twenty years. In addition, we cannot be absolutely sure of the survivability of the cryptocurrency, and therefore no one knows what will happen to it in a few more decades.
The world is becoming digital, but you should not get too carried away with this, since high technologies are very vulnerable, especially in our unstable time with constant wars or threats of their occurrence. Therefore, digital currency must exist in parallel with other types of currencies.