This is what Tim Draper said at the Web Summit summit conference in the 6th of November:
“Yes. We are talking [...] about five percent market share to get to $250,000. That seems like a drop in a bucket and all we need to really do is make it so that Bitcoin can be used to buy Starbucks coffee, and all of a sudden the world just opens up and then they say ‘I’ve got this choice.’ [...] Do I want a currency that I can take from country to country [...] or do I want one that sticks me in one country or one geographic area and I can’t use it anywhere else?”
Although I don't think that taking hard currencies from country to country can be associated with any problems regarding their exchange or even direct usage, I want to agree with his optimistic prediction about Bitcoin price in 4 years. Indeed, it is very likely that BTC will be adopted much more than it is today and the demand will rise drastically because of that, while the supply will definitely diminish. (By "supply" I mean not only newly mined coins, but also the coins flowing to the market from the whales' wallets).