I think there is a possibility someday that this dream will turn into reality all of us will become maillionaires. 1 BTC is $500,000 this is wow awesome. But its all depend on the demand and supply of the cryptocurrency coin like bitcoin when the demand is high there is a chance that there is a lot of buyers and investors. When the supply is not enough the price will go down. There is a thing called risk when it comes to this kind of money.
It might come true someday but it will take more time to get to that value and i strongly believe that it will gonna happen someday at least we are still alive to witness it. Bitcoin is the future if you are planning for long-term investment and this half a million dollar for a single Bitcoin will come true someday. Today it's just a dream that we keep on praying that might happen soon.
Our understanding of cryptocurrencies is still imperfect. We know the maximum number of Bitcoins (21 million) and the velocity of circulation of major currencies. However, we do not know how widely Bitcoins will be distributed in the future, how often operations with them will be performed, and for what purposes they will be used. Thus, Bitcoin can cost 20 dollars but half a million can be also a possible price.