One of the blockers for gamification is often staff feeling insulted in some way by it. Whether it is because they feel the money could have been better spent, that the concept is beneath them or just that they are resistant to any change at all.
It is true that gamification is often used in enterprise when someone feels there is a need to increase productivity in some way. That may be by using metrics delivered from a gamified environment to map pain points, or areas where there could be productivity increases. It could be by improving the training materials, or making them more palatable. The point is, these are all things that employees have to buy into for them to work.