This reply came from Stu Thorn @ Cyclocross World.com. This begs the question: What event can the Winter Olympics forego to add CX? I guess I'm on my Bloody Soapbox~ no one else seems to be that interested.
I will do my best to answer this one. From what I understand there are a couple of reasons. All winter sports must be played on snow or ice. I don’t see this as an issue as the Worlds in Tabor were on mostly ice and snow, but apparently the Olympic folks see this as a stumbling block. They could make snow for the better part of the course if they so desired. The other simple reason is that there is no room for another sport. They would have to drop something to take on another. This has been done in the Summer Olympics as was the case with Mountain Biking in 1996 in which they dropped one of the track disciplines to accommodate the MTB event. Some day the Olympic gang will see the light.
I remember reading about this in velonews a few years back. One major qualification for a sport to be a part of the winter olympics is that it has to have representation from 35 countries from 3 different continents. Also, the main man in charge at the winter olympics is from Belgium and he said that CX will NEVER be an olympic sport...