if I have to be honest, I do not think that the bitcoin will ever do this anytime soon but I also think that it will never happen, its just too much to ask from the bitcoin.
that's for sure. Too different opinions people have about Bitcoin. He can not become a substitute for a full-fledged currency
I think bitcoin and dollar can not complete each other since bitcoin is decentralize currency and dollar is centralized currency, bitcoin is good in online transactions while dollar is for daily expenses.
They are comfortable in the sense that they can work together to make this world a better place to live, without dollar or fiat bitcoin is nothing because our value relies solely on fiat, so if someone is saying that bitcoin might replace the dollar soon, it is just tantamount to saying bitcoin will die soon.