It's hard to say why the collector accepted such a low offer. Some have speculated that they were tax loss harvesting to offset other gains, while others have wondered if the collector's account might have been compromised. It's also possible that the collector was cutting losses, not expecting the demand for their NFT to rebound anytime soon.
In October 2021, an NFT collector dropped 300 ETH (then $1.05 million) on CrypToadz #2155, a pixel art image of a blue toad skeleton on a blue background. On June 13, they sold the NFT for 6.9 ETH (~$8,300), a $1.02 million loss.