With price reached by bitcoin in this year, it seems that the 20K USD price is possible in the next year (2018). I know that all people are surprised that bitcoin hits 19.6KUSD in this year because we just expect that by the end of this year bitcoin will just hit 10K USD. But bitcoin easily pass 10K USD. Even though now bitcoin is dropping, I believe it can easily recover then hits 20K USD so fast.
But I think the price of eth in the picture posted in the twitter which is 15k USD is possible in three to five years. Right now, eth kept on rising and from 600USD it already reached 900 USD.
The fact is that maybe I do not understand something, but Bitcoin in some countries and on some exchanges already traded for 20,000 dollars for one coin. Therefore, I believe that 2017 was marked by this maximum record of the price of Bitcoin.