Since it's talking about putting requirements first - arguably if it's possible or easy for a project to have all the specs immediately ready, it is also likely

Since it's talking about putting requirements first - arguably if it's possible or easy for a project to have all the specs immediately ready, it is also likely an easier project that has been solved many times in the past. There are projects for which you can't know everything ahead of time and you need to iterate and seek customer feedback. These are likely more innovative projects, and of course more risky and more likely to fail.