Could Coinbase have done an Initial Coin Offering (ICO) to raise money for their investors and employees instead, where the coin tracks revenue or something?
"Bumble and Badoo are two of the highest grossing online dating mobile applications... generated $376.6 million... in the period from January 29, 2020 to September 30, 2020."
Others who are happy with the gains they have made, and think it's too risky to keep holding. I've got a friend who sold his bitcoin recently to buy a house.
Unlike companies which have revenue as a marker, the bitcoin price seems very speculative, and if you think others might sell at 40k, you might do the same.