D&D brand name carries a lot of weight in the general public. Its known as the name that attaches to sword and sorcery game of imagined adventure with your friends. Most people in their 30's and 40's that is the name they associate to roleplaying games. Its the brand that is in pop culture.
Likewise, D&D has a strength that none of the other systems have, its settings. Planescape, Dark Sun, Forgotten Realms, Ravenloft, Spelljammer, Greyhawk, Dragonlance...
Those carry weight. If supported right, they will bring people back.
From a branding point of view, yup - D&D includes sub-brands which are stronger than most games' main brand. That said, branding isn't the be all and end all of sales; the tabletop gaming market is a very focused niche market witha high percentage of knowledgable customers on whim the branding isn't needed.