I guess I felt that the spirit of mountain biking was the after party. The after parites at dirt races in the '90s were GREAT...lots of people, food, beer, prizes, occational nudity...! The races were races though to all but the beginer class. I doubt that the sport class, expert class, or pro class dampened the mood of the beginnners. By the time I stopped racing 10 years ago though, the begginers all had coaches, nutritionist, and at least two $10,000 bikes. Talk about a change in the spirit!
I don't remember where I read it so I can't give credit, but someone wrote that 'as soon as beginners started shaving their legs, the sport was doomed'.