Just spoke with several financial experts with backgrounds in the banking sector. They told me once Japan opens itself up to the Bitcoin the currency is very likely to reach the 30.000 USD mark before 2020 since
Japan has been known to be a trendsetter and have high influence on the EU and US markets.
I'd have to say that you have to be pretty optimistic to predict these figures, however i'm not saying that they are impossible at all. In fact John McAfee said that bitcoin will be worth around $500k by around the same timeframe.
And it's not just Japan adopting, it's also Australia and they are a big economy. Plus, halving is on that year as well making the pump more likely.
Though, i think that maybe half that price is more likely. $15k per coin is a good prediction for 2020, but $30k is a bit of a stretch.