Holders already expect that bitcoin's price will go down big possibilities and same to Ethereum so many of holders already sell early for their altcoins so they dont loss big enough.
Yes some of them do expect price to fall, but there are a lot of them that are not aware that the price will fall. Some people, especially newbies, think that they are not going to lose money by investing funds in crypto.
They just think that crypto is a place for making easy money and they can just fund a wallet and expect it to multiply and make them thousands of dollars. But at last when it turns out to be the reverse of what I just said, you will see a lot of them calling it a scam.