I have been kicking this around lately...
OK, lets look at what they have done.
They have created a universe that is as deep, immersive, and varied as Star Wars. This has led to the establishment of a line of books that almost rivals Star Wars and Star Trek. Not to mention the fan generated material.
They are established in multimedia. Books, board games, RPG games, computer games, miniature games, and magazine(s)?. I am not including the blogs, forums, and websites dedicated to the various games they produce.
They have a fan-base that is as fuelled by rumors as a bored housewife. Despite a tepid economy they continue to raise prices on their products and release new material.
What is surprising is that despite a near constant swell of discontentment for their various practices, such as raising prices, outdated army books, no long-term release schedule (available to fans), lukewarm support of the tournaments, a flawed rule set, and constant changes wrought on the systems by army book rules exceptions; they continue to thrive and we ask for more!
They must have unlocked the secret to corporate success.
They do not (seemingly) listen to the fans, they ruthlessly enforce their IP even if it hurts their image, they do not advertise, they raise prices when the market does not seem to indicate that they should, they do not have sales, and they show no loyalty to their employees.
I have to admit...they seem to be doing everything wrong but succeeding despite that. I remain as dedicated a 40K enthusiast as I ever have. Despite some of the luster being lost because of how they operate. I still ante up to play in and read about their wonderful universe.