When Susan Aker writes about the work being owned by no one, she is referring to the intangible component, not the physical implementation of it. She doensn't say anyone might steal your car. The question is whether, if I have a Star Trek style replicator, I may legally use it to replicate your car.

The constitutional purpose of copyright is to enlarge the public domain. The creation of rights in the work is merely a means to this end. The details of the means must be subordinate to the end, which is public domain status for all works of the human mind.

T.