Enjoying the examples on the site. It'd be great if some of those companies shared more data on how things are working for them. Maybe you can extract that from some of them :)
Not all of the companies are successful or have been successful. They were successful at a specific point in time, doing a specific thing (like getting through problem interviews, for example) but it doesn't mean they were big hits as companies.
And many of the cases studies are about companies that were struggling with problems and managed to improve. The e-book specifically (and Lean Analytics, the book) aren't about understanding why startups failed, they're about how to use analytics to minimize failure and iterate past it.