I think BTC to hit $40K by end of 2018 is beyond reach. The current status of BTC seems it just hover below $20K. Llew CLaseen just made a wild prediction to encourage investors to place money on BTC after a huge lose.
I think getting to $40K is really achievable considering some things and since we have a lot of FUD out of the way and Bitcoin is steadily rising from $5K to $10K in a matter of weeks, I don't see the prediction to be wild at all.
Yeah, it is reasonable, and a lot of things are changing with the bitcoin's protocol development, but at the same time, we also have to leave some room for some possibilities of not seeing that as well.
It is bitcoin, the market is filled with huge monopoly whether we like it or not, so we cannot really say what the market really holds in the short or long term but to just believe that either way, it is a strong one. Whatever bitcoin will hit by the end of 2018 is only known by time.