The cryptocurrency market is usually crazy, and the cryptocurrency market in 2017 rose wildly, creating a lot of bubbles. So when these bubbles are punctured, the cryptocurrency market will continue to decline, which is the regularity of the economic market.
That's right. At the same time, the market is pumped up with money and then the prices of cryptocurrency grow. Then the money is drained from the market and then the prices fall. Huge money is earned on these operations by large "wallets".