Did they quit and join a competitor who offered a better WFH option? Or did they get a taste of the good parts of white collar pandemic life --- no commute, flexible hours, work from anywhere --- and decide that actually, their entire identity is not just their professional life, and maybe they should retire to see the world/spend time with family?
There are definitely some high profile rage quits over return to office, but I think there are a lot more of the "hey this was fun but time to take care of myself" quits.