Money doesn't have to be your motivation; Learning and doing something you have interest in can be more valuabe.
You can establish your retirement funding to cover things regardless of you working. Anything you earn would be added to your overall net worth, not increasing your budget or spending. It can free you to purposely target opportunities based solely on interest.
The ability to leave it at the end of the day and not take it home
What yo can enjoy most about scaled-down retirement jobs is being able to leave it all there at work. It can no longer be your job to take care of the world. That was left for the career driven go-getters who still needed to.