If someone bought $100 of Bitcoin in 2010 and kept it until now, they would now have around $6 million.
Do you think the same could happen again in the next 7 years? If I now own $500 in Bitcoin could that be worth $1 million+ in the next 7 years? Or is it extremely unlikely for this increase to happen a second time?
There are too many factors that defines the ultimate fate of the bitcoin and its prices. Going that much higher is speculated by many investors and big players but there is also downside of the coin. Its decentralised and no government will tolerate that much hike in the rates of bitcoin because it will simply kill the market of national economy and could lead to threaten situation. So before you can reach that price it may get legalised or capped at some rates.
If Bitcoin remains only an asset for speculation, no government could care less about it. It will become a threat if it starts competing with local currencies but that doesn't depend on its price. It simply can't really kill the economy if it stays away from it, and as long as it is used for speculation purposes only, there is no threat to any government. On the flip side, though, if people start to actually use for commerce and exchange of goods, governments may have to interfere indeed.