Because execution is often the difference between success and failure. There was a social network before Facebook. Actually there were several. MySpace comes

Because execution is often the difference between success and failure. There was a social network before Facebook. Actually there were several. MySpace comes to mind as the biggest. Even without Facebook, MySpace was on the way out. The difference? Execution. I could give the same movie script to 10 different directors and fund the production of 10 different movies and I guarantee you that at least a few of those movies you won't even know if they used the same script. People interpret the same information differently and have different visions based on that information. One might make it a RomCom. Another might decide it's an action movie. And if one of them makes one that people overwhelmingly prefer and it makes a billion dollars, would you suggest that they give the money back because there should only be so much success afforded to a single person when 10 different people all had the same script? You seem to imply that there would obviously be an operating system without Gates so why should he become rich? Well, there were several different operating systems, some might even argue superior operating systems, but they failed as businesses. Coming up with a new or revolutionary idea is hard. What's equally difficult is turning that into a successful business. Microsoft could have easily been a total flop had it hired the wrong people or made the wrong decisions. Google could have ended up as neat little experiment that never quite got off the ground had they not brought in the right people. But that's not just tech, that's not just business, that's life.