1.2 million of Ethereum has been abosorbed by the market. So the price did not drop and in fact rose. Yesterday's drop is just a correction.
1.2 million Ethereum isn't necessarily a lot if the market is big enough. If even a small fraction of stock traders were to get interested in Ethereum, and further suppose they bought the minimum rumored PoS staking amount of 1500 Eth, you would only need to get 1,000 people interested to sell 1.5 million. While this may sound like a lot, it would be a minuscule fraction of the amount of money tossed around each day in the world's stock markets. And this is just assuming the minimum investment, I am sure many traders would be interested in far larger "lot" sizes if they are looking to get involved.