For me that is not impossible to happen, but i think it will take 4 to 8 decades before it will happen. Especially if some government will intervene and won't promote the public information of what is bitcoin, and worst case scenario they will ban cryptocurrencies including bitcoin like what happened to China and it's neighbors.
even though we already reach 4 to 8 decades i still dont think that bitcoin can reach 1 million diollars .
Why i can say that? Because 1million dollars is too freakin high and verry unusual for just only a digital currency. it is also impossible for all of the people in the world to get involved in bitcoin because of some valid reasons , that is why bitcoin wont reach a verry high value because it cannot possibly get a higher demand from the public.
Though i believe that bitcoin can still reach a new all time high in the last period of this year and on the upcoming years and decades.