Actually, members frequently enjoy helping others, and any such tome would be hundreds of pages long.
As it is, people don't read FAQs, nor research the topic in Forums. SD Support is prompt and frequently Neil answers the questions himself.
The thought that this magnum opus might replace SD Support while nice, simply isn't realistic. I can imagine the supersonic howl tearing dogs' eardrums on Alpha Centauri, "SD sells software without support???!!!". Besides, there are always new problems and unique situations, so no money would be "saved", and on which page would "Did you plug in your computer?" be on?