Robot Workers of the World Unite?

It just occured to me that there is a definitive argument against the Marxist claim that the workers are the real owners of the products they create. Consider this: What is it that laborers do? They transform matter according to some pattern -- a pattern created by someone else. That would be one argument against the Marxist view, as the workers couldn't do what they were doing at all unless someone had created the pattern for them to transform matter into that particular pattern. But there's a stronger argument than that. As physical labor becomes automated, you wouldn't expect anyone to argue that the robots doing the transforming-of-matter-according-to-a-pattern are the "real" owners. If it makes no sense to argue that robots making something according to someone's pattern own the produced good, it equally makes no sense to argue that a human worker should own it. In the former case, one pays to buy the robot to do the work; in the latter case, one pays the worker to do the work.