Economies can only rise so far before they smack into a ceiling, also known as undergoing correction. Like a tilting boat, as soon as one person moves away from the one side, the boat tilts to the other side, and everyone else follows suit, and then the boat takes a massive swing to the other side.
All these altcoins are swinging around at the moment, undergoing a correction.
But I don't really know too much about economics, so take that as you will.