I think we all want to see more, but it's not just the quantity if games that needs picking up a level, it's the quality of them aswell. Like you pointed out 3 Forza's...why?
I know they sell well, and as far as that genre if games go then it's up there as one of the best, but I'd there really any need to invest time and money into bringing out a new one every 12 months when other genres of games are getting looked at.
Look at what Konami did with the next gen version of Silent hill for example. Made it, advertised it and then shelved it and it will never be released. Why?