There is a reason. Kids' games are designed to be intuitive and fun. Applications for adults are designed to be duller than dust.
Computer games are high in engagement but low in content.
Business, by contrast, has lots of content but little engagement. Put the two together, and you just might have something. That is what Prensky has done. His company, Corporate Gameware LLC, has created over dozens of high-tech training tools that mimic the excitement and drama of computer games like Doom and Myst, and mask the mundane, traditional tasks of training and testing. It is a revolutionary idea.