Similarly, my 85 year old grandfather still doesn’t own a wheelbarrow and will move stone, dirt, etc every summer. His motto is “keep moving”, I don’t think there’s really anything else to it. Yes you will slow down, but stay engaged and motivated and frankly you’ll outperform anyone because you’ll also have experience.
Some people flourish with age; some don't. Each individual's situation arises from a confluence of factors, some within their control (lifestyle, attitude, attention to professional development) and some outside their control (industry changes, ageism, health).
To contribute an anecdote from my own experience: I once worked at a consultancy with a large number of recent grads and one engineer who must have been in his 60s. Through a combination of hard-won expertise and a soft-spoken humility and sense of humor, he had the quiet admiration of all the young people in the office, to the point of coworkers privately raving to me about how great he was to work with.
Keep learning, keep moving your body. When you're 15 this is easy, you don't really have a choice. When you're 40+ it starts to become more of a deliberate act.
When I visited a hospital recently, the healthiest-looking person in the 106 years old. I know it because the nurse was super excited talking to her and asking if there is any special secret to staying healthy that long. Statistically, though, the health does degrade with age.
Outliers and anecdata are good for storytelling and inspiration, but the type of data you want to use for decision making is relative probabilities on a statistically significant set.