Unless you work with it, you can't appreciated how complex and convoluted U S tax law is. As I mentioned, I'm an accountant. I worked in commercial and multi-family residential (apartments) real estate. When tax time rolled around I got the financials cleaned up and turned them over to a CPA firm that specialized in tax returns. This is extra complex for nonprofits. With something the size of the Watchtower it would take years to unwind. If nothing else you can't just sell it all. In all probability they'd file bankruptcy and the court would appoint a receiver to manage the liquidation.
I doubt very much that the WT is ready to distribute all of its Billions in assets to another non-profit organization. They will always adapt and restructure TO STAY IN BUSINESS. None of the GB can run away with the monies. There are strict laws in the United States that govern non profit organization. (They are just Restructuring as they have always done since the beginning. This might include selling tons of KHs)
They can't sell it to themselves under a new name, either. That is one of the specifics of tax law regarding non-profits.