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.
It will be used a lot, yes. But not by everyone for sure, because people still will be afraid of bitcoins, not everyone know about bitcoins yet, so it will take more time than that
No more than 0.1% of the world population will use the bitcoin in 2022. If it does, the price will be $100,000 each.