I don't think 2020 will be bearish. Maybe at first the price action might appear to slowly decline. But then it goes into ranging and it will showing flat and low volatility movements but later on especially after the bitcoin halving, it will begin to climb.
This may be possible, but there are plenty of issues and news happened already after the ATH of 2017 that make bitcoin too popular positively and also gives negative impact in other nations that brings crypto/bitcoin price declines fast after the ATH. Halving will make the price increase again but not to the extent of having a bull run again.