Money Money Money
Were you pro or amateur?
To make money and pay professionals you need to package a sport for the media. That's possible for moto-cross, because permanent venues, outdoor and indoor, with provision for media resources, rider safety control and spectators are relatively inexpensive. Since they're races, comparison of times across months and years of competition is possible.
Gravity games are demonstrations of skill, like diving and figure skating, but much more dangerous. A death or two on live television wil probably kill the sport, so they need to control themselves.