Many old people work to keep active, and not because they need the money.
My younger brother always loved working whether out in the fields picking fruit when we were kids or working in his medical practice.
I was just the opposite; lazy to the bones when working on the farm, but loved my career as an Accountant. Retired early at 63, and enjoyed some world travel. Just returned from a two day trip to Yosemite National Park. Loved it!