It is said that bitcoin will destroy the fiat system but i believe that if this happens the world will change completly because banks and a lot of things will go out of market.
I think it is impossible that all people will use digital currency in 2022. Its too early for that. I think it will take a long time for about 5-10 years because the idea of bitcoin is complicated. Not all people can have access to it because you need at least a device and an internet connection for it.