ETH is still affected by the price of Bitcoin. Although ETH has a much better background than bitcoin. But maybe people are still supporting bitcoin more than ETH
People support Bitcoin because they don't know how to properly price an altcoin. They also don't care about their technological engineering.
Bitcoin is as simple as it can be, but this simplistic piece of technology has the least obstacles to struggle with, and the least to worry about when it comes to its future potential. If altoins weren't tied to Bitcoin, they wouldn't even be worth a tenth of what they are worth right now. People seem to think that altcoins are worth what they are worth, but that's wrong; altcoins are worth what they are worth because Bitcoin donated that value to them.
An altcoin can just keep its ratio at 0.01BTC for ever, but will still increase in value due to Bitcoin increasing in value. Litecoin is the perfect example of that. It was worth like 0.02BTC back in 2013 which was like $2 back in the days. Right now Litecoin is worth like 0.0125BTC which translates into $85 today.