Right now it seems that all alt coins' performance is tied to Bitcoin performance.
It is called correlation. They will likely be correlated for a long period of time.
Do you think that someday ETH price movement can be separate from Bitcoin's?
I don't think it will ever be separated, or if that happen, it won't happen soon.
People should stop looking for this to happen. I think the alts have other more pressing problems, for example, how to survive this bear market.