Copyright law differs from country to country. It gets EXTREMELY complicated as the US laws pertain to the US, yet most countries try to cooperate on enforcement of rights from one country to another. There are specialist lawyers who job is purely how to deal with one countries IP law.
"why can movie companies take an off the shelf item, Modify it, and then claim to own the copyright, trademark, or likeness of it? Does anyone have a good answer for this"
In the case of Lucas, sometimes they have gotten lucky such as a more modern product and the originating product company not going after him. In other cases, the companies have gone out of business and there is no one to pursue an infringement case. In other cases, the base item has been altered so much that the function, use and recognition of the item is altered to a point that it hits a very grey area of enforcement due to those changes.
This is where it can get extremely complicated and where a good lawyer can make a difference in enforcing / defending their intellectual property rights.
"why can movie companies take an off the shelf item, Modify it, and then claim to own the copyright, trademark, or likeness of it? Does anyone have a good answer for this"
In the case of Lucas, sometimes they have gotten lucky such as a more modern product and the originating product company not going after him. In other cases, the companies have gone out of business and there is no one to pursue an infringement case. In other cases, the base item has been altered so much that the function, use and recognition of the item is altered to a point that it hits a very grey area of enforcement due to those changes.
This is where it can get extremely complicated and where a good lawyer can make a difference in enforcing / defending their intellectual property rights.