Regarding why there isn’t a dedicated tool yet, I think because the elements of whatever we call a ‘serious game’ can vary so widely, in spite of a catchy, succinct name. If we can define a specific type of serious game, we can adapt the tools to streamline that application, but we’re nowhere near that point. Until then, we have to identify the presentation elements we feel our ‘serious game’ requires and use tools to produce those elements, whether they be from game development platforms or training development platforms. It may sound sarcastic, but I would include PowerPoint on your list of platforms — why do serious games have to involve heavy use of technology?

I’m sure software platform vendors would love to create a dedicated “serious games development engine” if there really were enough of a consensus about which specific problems any type of serious game addresses, and if there was a dedicated pool of money to go after. However, I don’t think we have reached anywhere near a consensus on such a categorization, and of course the size of the market (available money) is always the overriding concern. In my experience, money people give lip service to training but it’s really marketing where dollars/euros/yen are invested.