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.
The value of Bitcoin is simply driven by demand and supply and no one would have thought over $4000 per Bitcoin was realizable a few years back, but here we are today with $5000 just in view. Given the exquisite and unprecedented attributes Bitcoin have brought to play in the financial sector, we can only expect that the demand for and adoption of Bitcoin would continue to soar and since price is hinged on that, then these projections are just a matter of time!