Altcoins were always behind, a specially after a huge dump - they stopped growing. I think that is because people stopped to believe in altcoins and they thought that it would be better to store their belongings in bitcoin.
They are not yet stopping to believe in altcoin. Just take a look at the market and how altcoin was growing even greater than the major coin. It must caused by bitcoin but people are not yet leaving the altcoin dude.
This fact is still happening in the market.