Unless they promised to withhold the letter until 50% signed.

Also I have enough savings and my skills are in demand enough that I wouldn’t consider signing such a letter much of a risk. The researchers at openAI are likely a good deal more in demand than I am.

While the financial future is significantly less certain than it was a week ago, many of those employees have RSU-equivalents potentially worth FU money. Even if you are going to land on your feet, it is still making a statement to walk away from that payday.

If you believe that your profit share is going to be worth much much more with the current board gone, then threatening to walk away to force them to resign isn’t really walking away from much.