Linux and breakfast cereal: Why are there so many flavours?

One of the most common complaints about Linux is that there are too many different versions, it is too confusing and difficult to know which version to use, or that the market or users in general would somehow be better served if there were less selection.

My response to this is… well, my real response is not fit to publish here, but perhaps I can make it clear by giving an example based on another real-world choice that most people have to make in everyday life. So here we go.