It's a longer term trend than just the new compound in the US, but it seems that has really pushed them over the edge. Wasn't there hints from one member of the GB that it was a tough call whether they did it or not?
Donations seem pretty stagnant, at least on a per publisher basis, in the countries where they have to release accounts. With flatlined growth, their revenue is flat. So if they're reliant on third world growth then there has to be a cross-country subsidy to maintain what they've been doing. So would that explain it? Over-expansion, over-optimism as they come up with new ideas which stretch them too far financially without the donations ever catching up? They may not have taken enough corrective action soon enough, doing the whole Jehovah-jireh 'Armageddon will be here next year' thing, and they're now forced to make major spending cut-backs.
Definitely think JeffT's point that their ability to sell land/buildings means they're still a long way off from a true financial meltdown. They have assets there to sell. They've already shown that they'll ride roughshod over local congregations to do that when they want to. They're mutating again so wouldn't surprise me to see them making even more moves to consolidate congregations in areas where either growth is absent or there's a real decline in numbers.