If bitcoin made a new All Time High record now in the crypto market, do you think Ethereum will also follow and break it's ATH last year January 2018 which is more than $1000?
We have always observed that if bitcoin rises in value, most altcoins follow as well. Even now that bitcoin has reached another ATH, altcoins are also increasing and now, market is in green celebrating the bitcoins new record.
I have an assumption of how it all works, based on human psychology.
So, bitcoin is at ATH for month or two, you want to get into crypto, you start to get involved into the market games, check out whats going on in top10 coins, make your decision because you see the potential behind ETH, then ETH grows off of this sudden interest burst.