sentences:  Activision Publishing chief executive Mike Griffith, in response to questions about Activision's approach to the "Guitar Hero" market, noted that "Guitar Hero" continues to outsell the "Rock Band" series in both number of sales and revenue, with consumers continuing to buy the separate games on the market, and considered the market acceptance of the multiple games as validation for their model.Regardless, after releasing 25 different SKUs (between games and bundle packages) in 2009, Activision opted to reduce that number to 10 in 2010, recognizing the music game genre was not as profitable as it once was.Activision later opted to put future development of the series on hold in early 2011 citing weak sales in the rhythm game genre, a move that many journalists attributed to Activision's earlier oversaturation.