You're not thinking widely enough. The following is not the real story, just an hypothetical example: You're Codake, a company that sells chemical photography

You're not thinking widely enough. The following is not the real story, just an hypothetical example: You're Codake, a company that sells chemical photography materials. Some person invents digital photography, you find out and buy the patent from them for 500K. Digital photography would hurt your profits so you just sit on it for the 15 years, maybe start designing some products around it in the last 3 years of the patent to be ready for when it expires. You made more money and society lost out for 15 years, all because the inventor probably wasn't used to seeing large checks and didn't shop around when the largest photography company offered them more money than they ever saw in their life. Even the inventor got screwed, by selling the patent they got a nice house even though it was probably worth hundreds of millions.