you should search more about what "bubbles" are and also while you are at it start reading a little about pump and dumps.
basically when price of something is fake due to manipulation or pump, it can not stay that way for long. eventually it will come back to reality and to a price that is closer to its real value.
wit that said, altcoins are still in big bubbles and their prices are a lot higher than their real values. that is why they continue to fall and each time you think the fall was over you see the fall continue some more.