My experience is mostly in high end construction in the Midwest. Maybe it's different depending on the location, but generally, the carpenter is making a good deal more per hour than a painter. This axom holds true for the apprentices and laborers who would be given this work on a job site. The more skilled labor should be devoted to tasks that promote profitability, especially in today's competetive marketplace.
I can already hear all of the decorators nationwide complaining that I just called their profession unskilled, so let me clarify. I know full well the gambit of knowledge that is required for fine finishes. If a decorator is skilled in, say, faux finishes or wall paper application, chances are his/her boss will not set him to filling nail holes, sanding, stripping, or other labor intensive task that doesn't require a vast amount of experience to be done well.
Furthermore, on natural wood finishes, good decorators will first stain the wood, then fill the holes with a putty that matches the color, not hope that whatever putty he uses will stain the same as the wood, and then apply the varnish. This work then clearly falls within the realm of the painter as no carpenter should accept the liability of damaging the finish already applied to the wood.
Any carpenter should realize the importance of a good decorator on his site. They have been enhancing the appearance of our workmanship for centuries. It just so happens that filling nail holes falls squarely in the category of a fine FINISH. A carpenter shouldn't apply finishes anymore than a painter should do carpentry.