It's just the way these alts dip when BTC is growing or when it's dipping that makes people turn away from it. The good ones are obviously the best to invest into for great profits. But one needs to be careful else, all the funds will be lost.
Then you just have to choose the best and higher profitable altcoin in the market.
The most common failure that investors and traders are just because of coins selection, they usually look into the price but not it's market volume. If we are good at this, we could assure that we can still make money.