Microsoft, for whatever reason, decided to implement an XID protocol. So how does Microsoft entice companies to invest in development; they implement and enforce a licensing requirement to protect the companies (Fanatec, etc.) willing to develop wheels for the Xbox platform. If there wasn't any licensing system, no one would be willing to develop for a niche market with uncertain return on investment. The license narrows the playing field giving the few manufacturers of XID wheels a somewhat known market scope. I think it is less of a money making requirement of Microsoft and more of a protection system for developers. So until the market grows there is little room for Logitech.
In the case of Sony, I think they were smart in going with the more standard HID as they benefited by the availability of devices already on the market for the PC's; a larger market scope. Because of the large market there are more "players" willing to develop hardware solutions.
In a perfect world, I would have a choice of 8-10 wheels compatible with whichever system I decide to race on (PC, PS3, Xbox, iMac, Wii, Commodore Amiga, etc.). But, we virtual racers are actually a very small segment of the overall gaming population.
This is a Forza vs GT thread so I should post something relative. I purchased a Fanatec so I could play any racing sim released. And in the case of cross-platform titles I have been switching to the Xbox as they generally run better (graphics, frame-rate, etc.); perfect example F1 2011). Yes, a Fanatec is a little pricey but the investment is less if considering the "scope" of use. I can easily switch between platforms at will. My "will" in the fall of 2011 and spring of 2012 is Forza 4. It does so many things right (I didn't say perfect!) for GT5 to see any playing time anymore. Maybe GT6 will catch up...
My $.02