Nobody can be sure if what happened in 2016 can also happen in 2020. Right now, because Bitcoin is getting bearish, we can read many negative leaning articles in many crypto-focused platforms which paints a darker Bitcoin market despite the coming halving. One is suggesting that the impact of the halving has already been factored into the current price all because any possible increase should have started one year before the said scheduled event. I am sure though that if Bitcoin will be making a slight bullish move, then the sentiment on the halving can turned into very positive. In other words, only time can tell what will be, we can only speculate, wish and even dream for that bull run to come in 2020.