Bitcoin can go only so long without any bull run, people will eventually get back to bitcoin and if they do not do that in 2018 than we will see one in 2019. However if we finish 2018 with a good bull run and before 2019 it gets a big run than we may not see one in 2019 or at least in the early months just like what happened to 2018.
This is the reason why it makes a better sense to at least be well informed when it comes to trading knowledge in the market to know the steps to take at certain points in time so as not to miss out a whole lot in the long run. If you are investing in any space, be vast to be able to make a good decision which is what smart investors do rather than hoping on things we cannot know.