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 can't verify this 5 percent price ratio to BITCOIN unless someone resourceful verifies this but if this is true, it might have to do with fewer coins we had at that time as compared to the thousand of coins we have today that bitcoin trades with and has diluted it's value.
Possibly the number of Ethereum tokens could also be the reason for the fall of its crypto command in terms of power or simply because we have better coins on the market that has cut though Eth.
AFAIK the number of