Very possible. $4000/BTC potentially be reach later this year. As demand and popularity of bitcoin continue to increase, many people in world are interested and have studied bitcoin and ultimately rule out to invest. And that could have an impact on increase bitcoin rate.
If only we can get a solution to scaling problem. $4000 not this year, i think the highest we're going to see this year is $2500. if scaling problem is solved, then there's a possibility of $4k and above.
Huge money have to come from somewhere. Not sure if you know how it works, but for the price to double, someone will have to buy everything at current prices, and everything is those millions of Bitcoins, at 1,5k each, that are stacked at exchanges. And it's not over yet, somebody will have to try selling those coins at over 2 times the price they were not that long ago and find a crazy mofo to start buying.
Would you buy a $4000 bitcoin now? I guess not. What about in 3 months? I'd still say nope. As you can see it's not that easy for 4000 to happen at all and certainly not this year.