MMA is as unpredictable out of the cage as it is

inside the cage. Constant injuries, fight cancellations, main event switches, drug failures. I can see why hardly anyone makes money promoting MMA. You spend advertising/marketing dollars to promote fights only for them to fall apart weeks and/or days before the scheduled event. 

It is crazy that the same characteristic which makes MMA so exciting as far as action within the cage makes it so frustrating as a fan to deal with when fights routinely fall through.