The drop is due to the problem of the high fee of bitcoin in December, and many people panic to either cash out or move to altcoins.
It is really urgent that bitcoin come up with a feasible, usable scaling approach in the next 3-6 months. Otherwise I can see things turn out ugly.
I am confident that the issues will be sorted out in a few months time and hopefully we will be seeing the lightening transaction implemented this year,bitcoin had a big rally this past year and never expect the same kind of growth every year,this year we might see a good rally in some of the major alt coins.