Imagine reading a series of books. You really enjoy them, and the story is building wonderfully. You finish the fourth book in the series and go to find the fifth, only to discover that there is no fifth, and there never will be – perhaps the author has passed away or has concretely retired from writing. Isn’t that frustrating?
I don’t mind taking my time. I don’t need to finish a seven-book series in a week. But I want to know all seven books exist before I start.
The Opportunity Machine 