There's 36 weeks left in the year, BTC is at $8500. That's $11,500 to go to break the ATH and touch $20k. Comes out to $320 per week. I don't think anyone would say a $320 weekly gain for Bitcoin is very much. Granted it has to average that over 36 weeks, but still, looking at it this way $20k in 2018, building up to a 2019 boom, seems like it won't be that hard.
Should be a good year for making money from these prices onward!
That is assuming if bitcoin continues its dominant growth shown through the last week.
I personally don't think that we're going to see an all time high being broken this year. We very rarely see markets make a full recovery and go on an ultra-bull run that fast, within 1 year. As I've said, I feel like although currently the rally may take us to $9.5k+, it's most likely not going to crack $10k yet. Even if it does, the downward selling pressure may start mounting soon after we're above 5 figures.
Also, bitcoin growth is never this regular. We never see every single week of the year being in the green.
I'm leaning towards 2020 as the next main bull market, it should be quite easy for BTC to crack the all time high set last year then. But this year, I don't think it's happening.
I didn't mean to say it will be regular steady growth, I'm saying all it needs to do is AVERAGE $320/week. This week has been a good week and its up $800 right now in the past week. And of course the previous week it was up over $1000. And of course there will be plenty of down weeks. But an average of $320 gains per week is not very much. That's nothing close to a year like 2017, thats just moderate growth over the course of 8.5 months. 2019 will probably be when the craziness begins again and it'll launch off of $20k. But hey maybe it'll take a lot longer and the next bull market won't come until 2020 as you suggest, but just saying before the next bull market happens, it doesn't even take much weekly growth on average to hit $20k again this year.