Last December something happened no one predicted or even thought will happen, problem is that hasn't happened before , not in any year before 2017, So whether it will happen this year or not is still unpredictable. Most predictions are focused on 2020 it seems. Every predictor has high hopes for 2020.

To reach that point (where they predict) BTC either have to increase it's value gradually or increase spontaneously like last December, problem of happening the second way is , if it increase like that there's a risk of going down, like it's happening now.