Because all of the entire crypto-currency market is dropping.

Eth maybe dropping a bit faster but in general we are in a bear market for altcoins and none of them went up in price for a loooong time. Which means eth is not special or privileged or something because eth will drop as well when the market drops, eth has nothing more that would make it special and rise while all other coins are dropping in price.

It will keep going down as long as all other coins go down as well, bear market affects all altcoins and whether you believe it or not ethereum is still an altcoin and nothing bigger than that. We will see it go up in price soon when the bull comes back.