I don't think that is entirely that impossible. I think that filling for bankruptcy would be a very bad move for them. Any move that seem voluntary and initiated from within would be harder to justify in front of the R&F. Not that they won't be able to justify successfully, I say its just harder when there are other options. Everyone donating $1 a month. I find that hard to achieve. Not everyone in the world can afford to donate a dollar a month, much less for the foreseeable future. There is only about 1 million JWs in the US. With that said, they probably would not take all of that money in and put it directly into cashflow. Most likely invested in some form of another, which means they would have to wait on the return to start coming in
Assuming all of the above is accurate to some degree, a re definition, re organization, re branding will be most likely and much more acceptable to the majority of the members.
If they haven't figured it out by now, asking everyone to pay a "membership fee" in order to get baptized could be much more easily swallowed than tithing or anything that pushes compulsory donations down and directly to the members. Provided that they crunch the numbers, it could almost work as a group insurance, where we all pay a fee, just in case one of the members slips and rapes a child.