Thats easy to understand one thing altcoins are all traded against bitcoin, soo any moove over bitcoin value will push up/down altcoins, some of them are able to follow bitcoin for a while since are based into it, but in the general the trend is to go at opost direction then bitcoin. Bitcoin where and still being the most power crypto and the first, altcoins camed after bitcoin trying to get similiar results and improve some issues that bitcoin could had, nowadays we do see a lot ico wich will be focus into some area, because bitcoin has been present at all, but isnt focus into nothing else besides provide a strong and safe way to moove money.