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.
BItcoin will be used by most people by 2020,but not by every one.There are still majority of world population in under developed countries who don't know about digital transactions.It would b hard for them to change to bitcoin transactions and it would take more time for all people to change to bitcoin transactions.
I agree, the more people will get to know bitcoin more and more people will use bitcoin, especially with higher prices, people will be more interested in bitcoin, but it needs regulation that set the bitcoin to be used by everyone