Bitcoin has a great potential to grow up because there are lots of companies and many more industries or we can say big industries which are paying the salary through bitcoin. If this thing happens more and more industries will come then buying for bitcoin will be increased daily and we can have our market cap as trillions of dollar by the end of 2020.
This is just the beginning of Bitcoin and today still only 5% people knows the real value and the future scope of bitcoin so it is for sure bitcoin price will spike up upto 50k USD as you are asking the same.
We cannot say it is going to happen in 2018 but there is a news of ETF at August 10 which seems 90% SEC will pass the rules and regulation and our bitcoin will come and step in into stocks as a shares.
Many bitcoin holders are expecting the price to be $25000 above this year after passing the ETF and this could be near in future soon. But if the ETF does not get approval then it is not to worry about the price as at from last 5 years we are applying to SEC and they are rejecting the form and still our bitcoin is going to its ALL TIME HIGH every year. So it is sure price will 100% spike up in this year and it will reach its all time high but the exact price prediction i think any expert cannot say because the market is fully in control of whales and they are manipulating the market.