In my opinion the amount of BTC held does not indicate whether the whales are poor or not. Who knows, those whales either sold bitcoin at high prices and held USDT or used that money to invest in potential stocks. just when they sense they can no longer control bitcoin well, they will split it up among organizations and unite, which is also a strategy to minimize the risk of fighting among whales.
There are also whales or large investors who are very smart and to save themselves from being highlighted and a possibility of being tracked they use a lot of addresses and keep small amounts in each of them. In fact this is very common too, no one keeps their coins in single address so while you might think that the whales are decreasing and market is getting more and more stable you never know what whales might be doing.
There was a recent scam with some plus token and they used to hold so many bitcoins but not many people were aware that there exist a giant holder like them only when they scammed it was revealed and that also tells you how much bitcoins are being controlled by Chinese investors.