Whats happening with Ethereum this year? What if the current trend continues? Lets try some painting ...
0.5 BTC/ETH? How crazy would that be? No too crazy if we assume following scenario:
In the first half of 2018 ETH will surge faster then BTC and BTC will fall to somewhat around 8k in the first half of 2018. 1 ETH would then be around 4k worth in USD. "Only a 4x" in 6 months.
In the long run, I honestly think it doesn't even matter. Ethereum is here to stay. You could even possibly compare the Ethereum Virtual Machine to Microsoft Windows. Given the markt share of Windows, ETH could easily reach 30k.
Just my two cents ...