From the 1978 Dungeons & Dragons introduction, page 5: "Dungeons & Dragons is a fantastic, exciting and imaginative game of role playing for adults 12 years and up."
If I ran a game-making company, I would probably try to be sure my products reach the largest possible market. And I think this is what this thread is really about: is it a better business decision to widen the market appeal in terms of age range, or to focus on a mostly-adult market with content specifically placed to appeal to adults who insist on pixual intercourse? Maybe we will never know, Leira willing.