I can't answer your question regarding who has the money, but I would like to suggest to you that the money isn't as important as you may think it is. I agree with Jnat that WTBS is a bureaucracy whose primary goal is self-preservation. Other large organizations are bureaucracies also. Let's say that Apple Corporation is one. The founders and leaders of Apple want to leave a legacy that will be around 100 years from now, so in that way they're no different from the leaders of the WTBS.
Apple, through its advertising, development and marketing of superior products, and manipulation of social media, labors mightily to alter my behavior. They may convince me that without Apple products, my life will be less rich and meaningful, and if I believe them, I buy their stuff. As an organization they have spent a good deal of capital to influence me to do so, and their motive is profit--so the money is quite important to them.
I don't believe the leaders of the WTBS are greedy in the traditional sense of the word, that is, for profit. They control an empire, and even if all of the perks that we've heard about are true, they still lead rather austere lives compared to the titans at Apple or any other multi-billion dollar corporation. Money is necessary to keep the wheels in motion, but it is not their primary focus. So what do WT leaders work so hard to attain? Power and control. Power and control are the keys to perpetuating their organization. They manipulate, not by the carrot of pleasure, as Apple does, but by the stick of fear and guilt. They preach that all not with them are against them, placing 99% of the world on the side of Satan. Add to that the specter of shunning, spiritual bankruptcy, the wrath of Jehovah, and finally an excruciating death at Armageddon, and they can exert a powerful influence on naïve people. It works on only one in a thousand, but it has created a juggernaut that is very hard to break up. That is what they seek. Power and control.