You can not rely on past records to make your speculation then decisions. Bitcoin and Ethereum are different cryptocurrencies and their prices will be decided by upgrades, developments on their networks.

What you said is relating to capital flow on the market. From Bitcoin to altcoin and Ethereum is the biggest altcoin. However capital flow solely can not help price to rise.

Ethereum can rise one, two or three moths after Bitcoin tops up. You can not certainly it will in only one month.