Patents deal with inventions. It can take years of effort and loads of money just to invent something, so by the time your invention works, you’re stuck in a pretty weird spot. On one hand, you could keep your methods secret and market your invention to the world, but other people could reverse-engineer it and compete with you. On the other, you could tell the entire world how to re-create your invention (that’s what a patent is), but in return you’ll get a monopoly over it for some time. That’s pretty much what goes in an inventor’s head when deciding whether or not to patent something.