I have thought about this question many times. I am a firm believer that if you want to sort out corruption, follow the money trail. If something doesn't make sense, see who benefits. There may not be money in some cases, it could be power, sex, or perceived affluence.
Let's consider each:
1) sex. Unlikely, the culture does not lend itself to the "free love" of some other cults. This is not to say there couldn't be a secret little sumthin-sumthin, but I think its highly unlikely.
2) power. There is some power, getting to decide who lives/dies spiritually, set procedure, rulings, etc. But the changes in doctrine seem to follow the change in the presidents, to me. So, in reality, there is very little power, although to someone who would otherwise work plunging toilets for Steven's Janitorial Services, that little bit of power could go a long way.
3) money. Here in lies the big ticket item... A retirement. These guys are not spring chickens. If the society collapsed, they would be broke and homeless with a few $ from SS, maybe. While the money may not be that great, and the accomodations are sparse (in theory), they are living at least as well, if not better than the average citizen who is that age. Perhaps not the biggest house on the block, but its 4 walls and a roof, meals, and medical care all paid. And they can keep it as long as they are GB or dead, as long as they don't get DF or DA, and the WT$B$ doesn't collapse.
4) perceived affluence: A combination of 2 and 3. This is not "wealth" or "power" that is measureable. It is completely relative. A guy in a trailer is rich to the guy in the shelter, but poor to the guy in a 1500 sq ft house. Likewise they are all poor to the guy with 15K sqft house, and all rich to the guy lying in his urine on a park bench freezing to death. The perceived affluence is huge for the GB. The make a call and it gets done, they want something, it gets done. They show up anywhere and its like the pope has visited. They don't eat at conventions, the ride in nice vehicles to 5 star restaurants and have the best food. They get limo service. The have the finest luxuries and best medical treatment. They would be zeros outside the GB, but they are rock-n-roll because they made it to the top. And yes, they lose all affluence, influence, family, and friends if they misstep, so they don't misstep. And, having conversed with CO and DO, I would assume the the GB would be even more arrogant and elitist.
Of course, just my $.02 and opinion. I know nothing, I theorize often.