2018 may be a market that has been falling, holding a better choice for your bitcoin in such a market.
I think Cryptocurrency sprang up everywhere like Bitcoin because this is the first of every peer-to-peer network, providing coins and trading platforms, also has its own blockchain, its current market capitalization, its price, its scalability, and its popularity is hard to ignore. and will stay for a long time. so the advice I would give is that any crypto currency that is not only there to serve as a coin or a trading asset but provide more services will definitely survive and you can invest in it in the long run.
No I dont think so because $50k is very huge price and there is a big difference between $50k and the price today. In the rest of this year I think that the price would reach approximately $20000. It is enough for bitcoin. Those investors that bought bitcoin for $18 or 19k would recover their deficits and if the price grows more they would earn some money after long wait.