"Although Steve Gundrum's experiment was hardly rigorous or conclusive, it does touch on a real issue with open source. Striking a balance between an architecture of participation and an architecture of control is a central concern for all kinds of product development. In the case of most successful software applications that ride above the commodity stacks, the balance we've struck so far typically locates participation outside the API boundary. Whether that can change, and whether it should, are two very interesting questions."
That does seem kind of true. The name Apache, belonging to another big open source application, came into being because people were patching up the web server to suit their needs. No architectural design their (or at least thats what I've read). Similarly for KDE, GNOME, and so forth. I'm not sure, but Gimp probably followed photoshop it would seem.