Prices and chart analysis are popular, but not so scientific thing. Unless if we are talking about whales and their influence. In the case of the whales, there is a hard belief, they manipulated the price. This may partially true. Before big dumps, the exchange inflows usually increasing.
Whales send big amounts for selling. But, there are no infinite stacks, all wallets could be empty at the time. Yes, whales can dump, temporarily. Grayscale, PayPal, Square’s clients, and users purchasing all the BTC from the market, more than the miners get for mining. They are doing it for long months. Soon or later, whales’ stacks will melt.