Every year is victorious for bitcoin as long as it gets developed and globally adopted more and more every year,
regardless of price.
if the drastic decline occurs again at the end of December 2018, then I think that bitcoin will fall $ 500.
It doesn't work that way. For BTC to drop from $6500 to $500, it would take another 171.42% decrease. The chances of that happening is extremely slim in my opinion.