[manarth]

A patent is a time-limited monopoly, granted as recompense for publishing the details of their invention.

Inventors can profit from their invention by selling products, and keeping the invention details a Trade Secret. For example, Coca-Cola is protected as trade secret, rather than by patent.

Naturally this is less useful for something that can be reverse-engineered fairly easily, like, say, something in tech.

  What inventor wants to patent their idea and why do they want to do such an awful thing?

These days, I think it's mostly out of fear of being sued by another patent-holder. Companies often stockpile patents to maintain the deterrence of Mutually Assured Destruction.