Owners of real, personal, and intellectual property do not have the same rights under the law in the United States for a number of reasons having to do with the nature of property, the development of law in each area, and the allocation of state and federal jurisdiction in this country.
First, real and personal property are tangible, something we can see and touch. Intellectual property is intangible. So, the means by which we protect and transfer or share rights is quite different. Personal property rights are generally rooted in possession, meaning that if I have something, there is a presumption that I own it. That is, of course, a rebuttable presumption, but this is generally the basis of one's rights in personal property. One's rights in real property are almost always based upon a writing, at least in the United States. The sole exception is adverse possession, meaning one gains rights in a personal property by acting as though one owns it for a number of years, but this is quite rare. Otherwise, all states require a deed to establish possession and assert the rights of ownership, against all others who might trespass or occupy. Intellectual property, because it is intangible, is different because one can "own" a patent or copyright that one can use oneself and still allow others to use it with proper permission or under the fair use doctrine. Thus, if I write a book, I cannot seek compensation if a teacher quotes briefly from the book in a classroom, one example of the fair use doctrine. The rights one has in intellectual property are not nearly as absolute as those of personal or real property.
A second distinction lies in the development of law in these areas. Rights in real and personal property in the United States are generally based upon English common law, meaning that most principles associated with ownership arise from cases decided hundreds of years ago. On the other hand, ownership rights in intellectual property are always statutory, meaning a legislature has created a specific law to deal with this kind of ownership.
A third difference involves the allocation of power over these very different areas of ownership in the United States Constitution. The Constitution gives Congress jurisdiction over intellectual property law, while personal and real property matters are left to the states. Thus, it is up to Congress to determine the process of creating these rights, the process by which one asserts these rights, and the penalties for violating these rights. A person who seeks to assert intellectual property rights does so in a federal court. No state can do this. The states, however, provide the case law and some statutes that are the underpinnings of rights in real and personal property, and most cases that arise in these areas are litigated in state courts.
How one creates one's rights and how one asserts one's rights in these forms of property is very different in the United States, for historical, jurisdictional, and very practical reasons.