If everything worked perfectly in cycles, it could be slow on BTC until 2020 with only small spikes in between now and then. This is just a cycle copy from what happened in 2013. But it's also likely that this cycle will be shorter in time as cryptos have picked up the pace in recent years.
In this, one of many possible scenarios, I've counted Elliot Waves and it seems that we're still waiting for the 5th wave down to come and sub waves confirm it. This is one of the reasons, that it got so slow, people are expecting one more down fall to possibly ~8300 area before trend changes.