If you had power over all music, what rules would you create and enforce? I would first promulgate that bands have to break up after a certain period of time. (Or individual artists have to cease recording/touring.) Part of the reason the Beatles or Nirvana are viewed as so influential is that they had a certain period of music creation and that's it. No long decline. No embarrassing albums that attempt to follow current fashions. No long cycles when nothing new was released. No later tours done solely to make money and gratify egos. They did what they did and that was that. (Admittedly individual members may have had longer more embarrassing careers, but that's a separate issue.) I'm not sure what the time period would be but 10-15 years at most seems reasonable.