Most predictions made by prominent people and by well-known investors in the stock market seem to quote somewhere around USD 50,000 to about USD 100,000 by the end of this year, but 2 years from now 1 MIllion seems a lot and ofcourse there's also the time involved in price corrections, market price stability and periods where Bitcoin and the cryptomarkets seem to be less volatile (like they are now where the price drops a bit, rises by a bit and then settles back to a lower state). Looking at this, USD 1 MIllion for a Bitcoin might be a very skewed prediction and would possibly just be an outilier amongst the other few predctions quoted below:
Thomas Glucksmann - Gatecoin CEO and A Blockchain Evangelist - Mentioned that Bitcoin could reach USD 50,000 by the year.
Tom Lee - Wall Street strategist - Bitcoin is essentially "digital gold" for millennials, and the cryptocurrency could easily achieve the $100,000 range.
Michael Novogratz - Ex-Hedge fund manager - Bitcoin could be at $40,000 at the end of 2018. It easily could," on CNBC's "Fast Money.
I feel anything can happen in the long run and Bitcoin will moon but during a short span of time having realistic predictions makes sense. I feel there are a lot of factors to be considered when it comes to Bitcoins price, mainly on-going chain of regulations, security issues with exchanges (unexpected events) and also the free market forces. All of these could add to the selling pressure, but a rebound is imminent right after that. But the point here is, considering these factors, the price will need time to stabilize, find its support and then we could see it possibly reach it's previous ATH (about $20,000) and could be a bit higher than that.