I think the wrong-headed idea that many nerds have is that creating a startup is mostly about having a brilliant idea. If someone comes along and creates something similar to their idea, they think "that could have been me."
I suspect that the real value comes from execution of the idea, perseverance, and willingness to let your idea evolve until you've created something that people want. Often folks fail to recognize that the ability to execute and evolve (and be willing to fail) are traits that we don't all have, and so it's very possible that it couldn't have been them.
While there are probably some ideas that are doomed to fail, I don't think that label applies to any of the ones from the original post.
I suspect that the real value comes from execution of the idea, perseverance, and willingness to let your idea evolve until you've created something that people want. Often folks fail to recognize that the ability to execute and evolve (and be willing to fail) are traits that we don't all have, and so it's very possible that it couldn't have been them.
While there are probably some ideas that are doomed to fail, I don't think that label applies to any of the ones from the original post.