Will Magnus is mentally unstable and in 52 it seems to indicate he has to be in his well off the meds state to 'invent' sooo odds are no one wants a Will Magnus Patent except supervillains because everyone wants something built by the unstable fellow that goes right into the person's brain amplifying sounds to extraordinary levels far beyond that of a regular person. We don't know if Hartley was a fluke or not either, one success doesn't equal medically viable.