Ethereum is the best partner of bitcoin, during 2017 ethereum prices were around 5% of the price of bitcoin. when the bitcoin price is $ 5600 then the ethereum price is $ 280
But why since 2018 until now when bitcoin has reached $ 11 707, ethereum is still $ 227. The ethereum price should be $ 585.
What happened

if bitcoin price is $ 20 000 then ethereum price is only $ 600

I think this is because ethereum prices are weakening against bitcoin. This is what makes the current dominance of bitcoin in the market reach more than 70%. But if we hold ethereum for the long term, I think we don't need to worry because ethereum is still a coin with great liquidity and is in no. 2 coinmarket