It wouldnt be 500K for at least 4 years.
maybe! but nobody was expecting $16,000 in 2017 either! back in 2016 and even in earlier this year, everyone was saying $1200 is the end and they were all seeing "Mt Gox 2013 bubble" all over again and were predicting $200 crash! and the bulls were predicting barely $2000 by the end of the year (now). and the rest is history.
the bitcoin rises have always been unpredictable. we may see it in 2 years or we may see a bear market for 1 year and then rise to it in 3 years. but i think it depends on how high the current price will go. if it doesn't go crazy and stops to consolidate, it may be reached in 2 years.