Once the same thing begins to happen to Ethereum like to Bitcoin, LiteCoin will take over, and the cycle continues with the next currency on the list.
This is my opinion, and I might be wrong because there is no such thing as "excluding all factors" in the real world, but what does the community think? How probable is it that Ethereum will be priced at $6000?
It will need a lot of time before Ethereum will be worth $6000. A good and possible taget for next year is $500-$600. Ethereum is a strong long term hodl!