I don't know what bitcoin price will be by DEC 2019 but one thing is certain,many new developers and companies are already using the block chain technology which is good for crypto world and this means that bitcoin price will be more stable than we've seen on the past so I'm less worried about the future of crypto
We must never worry about crypto mate and-most specially for Bitcoin because we have already saw the growth from 10 years ago when bitcoin was first introduced and compared to the value today
In December 2019 the bull market was being speculated to continue so we might see a growth maybe not like what we have in 2017 but in the following years we will see the highest value that the bitcoin may bring to us