Well, one reason is that more people are now aware of btc and every single day there are people who are deciding to join the trend. And let's not forget the upcoming fork which is the segwit2x. This fork is more serious and better than the last one (btg). More investors are buying in to get more b2x as much as they can which adds to the surge of btc. Just when I thought we'll settle at 6k before the year ends, and now we're at 7k. Amazing!