The volatile nature of the cryptocurrency market is due to the fact that cryptocurrency operates on a decentralized system and its price is most determined by those who have a lot of a particular crypto coin. If i have about 1000 Ethereum and i decide to sell it at $50, this will force others to reduce their price in order to sell their coin because a drastic decrease in the price of ethereum.
People managed to collect a lot of top coins before the market was finally formed, they now have large reserves of coins on their hands and therefore influence the price or even the entire market