If marketing to adults I'd publish one hardcover, max 256 pages, complete game, streamlined system.  "Dungeons and Dragons" core rulebook one and done.  Commercials/advertisements would focus on adults sitting around telling an exciting story.  A nice game night with friends.  Easy to learn, easy to play, unlock your imagination and take a few hours away from your regular responsibilities (children, career, etc).  Sure, television and movies are fun, but don't you want to tell your own stories?
As a business model I don't know if it's any good.  I just think if you say "Here's 920 pages of rulebooks to read first..." you'll have lost 90% of your intended market (adults, people over 25 for arguments sake).