5000$ is possible to be acheved at this moment. 10k and 50k will be achieved, in my opinion, if Bitcoin will be legal to most of the countries. Bitcoin is still young, it is still on its way of growing and it's not even on the middle or I must say this is only just the beginning. More people are being interested to Bitcoin because of the profit that it gives to its users. The demand is continuously rising and will be expecting for more.