About painters and other visual artists, it's true that many were still working and producing in their final years. OTOH it was often the case that in old age they worked in relative obscurity as younger artists with "modern" styles had become the ones sought after and celebrated.
I've come to understand that the merit of most contemporary visual artwork won't be decided until 50 or 100 years down the road. In his time Rembrandt was known mainly for his magnificent etchings, printmaking was his main business. Now we celebrate his paintings as much or more, but we have the luxury of centuries to have honed our esthetic metrics.
My hunch is that creativity among physicists is the product of a special kind of insight, a moment when a number of seemingly disparate (and possibly mundane) phenomena suddenly align within a brilliant mind. Maybe this is a pretty common experience, but in most instances the insight isn't about anything really important to the rest of the world. Mostly it's something that happens early in life, young adult years most likely. Careers are about working out the details and reducing it to words (and equations) others can understand, a very hard task to accomplish.
While much has been written about creativity we really know very little about what magical things make it happen in those rare and enchanted brains.