Alas, the people in the scarlet chapeaus have threatened me with severe punishment if I even breathe a word of what's under the hood. Since I really enjoy writing with all ten digits in perfect working order, I have opted out of discussing that topic. The last time I saw an NDA like this was from Redmond when I was testing Windows 95.
Human beings are very acquisitive creatures.
To paraphrase George Carlin, we love our stuff. Someone in this worthy pack of competitors wants to be number one and thanks to human nature, they want to stay there. Already companies are starting to change little bits and pieces of the GPL to suit their needs in a way that make them seem altruistic when they really aren't. Vita Nuova is planning on releasing the source code of Inferno as a way of providing its customers with the tools they need to customize the software to their liking. I said customers, not the general public.