That's nonsense, plain and simple. If you believe that I have a bridge to sell you.

Sure, the employer may not have done any work directly to the widget, but they have provided a place to work with the necessary tools and quality control, as well as providing a steady source of work, regardless of if one particular product fails or succeeds. The employee is offering work in exchange for the above, realizing that while he could work on his own, the capital costs and potential for failure are greater.