I don't know about about United States law, but at least in my country and many others, the general rule is that copyright belongs to the principal (the one who pays for the services) unless the parties stipulate otherwise....
For example, if I pay someone to take pictures of my marriage, I have the copyright of those pictures, not the photographer, unless stipulated otherwise in a contract.
I made a quick search and it seems that in USA, if a work is created by an employee in the course of his or her employment, the employer owns the copyright.
So no, it may not be as simple as you say and you definitely shouldn't be trying to teach other people about this topic lol