That's ridiculous, he (or she) doesn't do it just for the money, the work itself is satisfying entirely separate from the monetary compensation. I'm sure he could find a job with pretty much the same income but less responsibility and therefore less stress if he felt like it but then he wouldn't have the satisfaction of building such an object.
I don't make watches but I do write some moderately complex software (I try to avoid it being complicated). It pays me the money that I use to feed my family but that is far from the only reason I do it. It is a satisfying endeavour in itself, sometimes just to see the customer's delight in using the finished article and sometimes my own delight in achieving a neat and efficient solution.
Back to physical things, I used to be a test equipment designer and the one thing I regret about moving into software is that I can no longer show my creations to people like my wife and have her see even a slight glimmer of what I have achieved.