I also think your core idea is plausible but I think you led into it with a couple non sequiturs, so you almost lost me.
First you talked about money grabs. Well, the Society needs money to run. We simply have no way to know what their expenses are for printing and other "Kingdom activities" so we don't have any basis for saying that arrangements like the new "eternal mortgage" indicate a lack of sincerity. Why can't the leadership be sincere while also looking for new ways to fund their work? Remember that expansion is taking place mostly in poorer countries now, so the average donation per publisher may be dropping significantly even as printing costs have skyrocketed.
Secondly, it isn't necessary for someone to be a secret non-believer in order to be interested in getting rich from doing business with the Society. I think there probably are some brothers who own companies that are used heavily by the Society. But this doesn't require them to be "secret atheists" or even sincere but hypocritical. Hey, if the Society wants to use their company, then who's to say this is unscrupulous?
I realize that you're suggesting a more thorough comprehensive bilking of the Society by some higher-ups, and I don't rule out that possibility, but I wanted to separate the most likely part of your idea from the more fantastical part. Personally I don't think that climbing the ladder tends to show someone that the emperor has no clothes. I suppose that has been the case for some idealistic brothers, but when you have a "company man" mindset, you don't get fazed by things that happen as you gradually get promoted through MS, elder, PO, CO, DO....