This article sure suggested it. Several years ago, DDR seemed to be "the shit" for rhythm based games, since they were relatively rare back then minus those in arcades. Overtime, the game was pretty much forgotten, and not many people have talked about it at all recently.Looks like Guitar Hero and Rock Band are just today's cash whores, but if the trend continues, they will hardly be talked about in a few years.
P.S. 19 DDR SKUs since 2002, and 25 Guitar Hero SKUs since 2005. Jesus Fucking Christ.