Yes you are right but not totally right, how? Not only ETH is affected in this case, even Bitcoin was affected other good coins were also affected, so i see it as a thing associated with bear market, which is, when it sets in, hardly is any coin spared.
It is because bitcoin is the major source of money for buying and selling the altcoins. Entry of fiat is limited here and thus this association.
Furthermore, being the numbers 2 in the crypto market shows the team is doing something right.
This is a flawed opinion. The one you are seeing as number 2 or number 1 or whatever is because of the market price and volume. They are not an indicator of the usefulness or development of the coin.
Whether one coin will be worth buying in the future is questionable if there is a sudden increase in price as well. Though for ethereum maybe a mid term sell would be a good option. So for that this is a good time to buy and keep in stock. Same goes with bitcoin.