In the past I think they've been wary of that for reaons of preserving a sense of brand identity and shared experiences of play.If they were ambitious, they would add elements to make the game modular, since people want to adapt it for every style of rpg anyway. The "DMs workshop" section of the dmg could be expanded into a full book that provides optional rules for each pillar of play and also advice on slimming the game down into something more rules lite and deadly. They could also provide optional rules for adapting the game to different genres.
I don't know if they still feel that way.