I think it's a human trait. In many places people imagine a successful life as enduring to get to some position and then being an important guy who can screw everyone.
And patents and IP indirectly perpetuate that worldview. "Invent" something and then live on royalties. "Discover" something and then that too. Write a book and then any reference to it means royalties. At least in dreams and fairy-tales it looks like that.
The incentive is privilege. It's a very old mechanism, not really making any sense for economics as known today.
That is, it makes some sense - before IP and patents people would have trade secrets. A secret technology of making some dye or some material or some kind of steel. Patents allowed for faster modernization - you don't have to keep it a secret anymore, which allows to scale production.
With things hard to cover by IP and patents they use the network effect instead.