Office 2009 on the way

Information Week, among other sources, is reporting that the next version of Microsoft Office is due out in 2009. With no official word yet from Microsoft, you have to wonder why they would be rolling a new version out so soon-two years after 2007, where 2007 was four after 2003. It seems like a sufficiently short timeframe that they risk cannibalizing their own potential 2K7 sales; people have been holding off on buying it anyway, how much incentive do you have to pick it up when you can hold out for a year and get the latest and greatest?
One possible explanation is that there are deficiencies in 2007 that they don't want to correct in that product (for whatever reason) but which represent liabilities in the larger market should they be left out there too long against competing products. I don't have any idea what those might be, but one might imagine that more online integration is in store.
Or maybe they're just being optimistic and we can expect to see enough slippage to make it "Office 2011."
Actually, before Office 2003, it was common practice for Microsoft to release a new version every two years. The four-year span between Office 2003 and Office 2007 was a fluke.
Good point–even less than two years, actually. On the other hand, I think it’s fair to argue that there were considerably greater differences (improvements, even) between Office 4.0 (1994) and Office 95 (1995). On the other hand, I think of 97 as more of a point upgrade to 95, and XP as not being particularly different at all from 2000. So I don’t think the increased span was so much a fluke as a trend, and the illusion of more frequent releases as more a factor of a fiddled versioning system that has been driven more by marketing than features.
I suppose it remains to be seen whether 2009 is a ‘point’ release to ’07 or not.