who know bitcoin will become in 2018 i think its not possible it become 50k USD 
Some speculators say bitcoin will reach 50K but not next year, more like 10 years from now i think it could reach 4-5K next year. But to be honest we don't even know what will happen to bitcoin in 2 days from now
I'm not sure about whether Bitcoins can reach 50K range even in 10 years time but very confident that it can reach around 5K in next one to two years time. It should focus now to resolve all those issues currently Bitcoin is facing. If that happens then it will attract many new investors and it pushes its prices to very high.