With all the down sizing and other money savings they have made, when the big money from Brooklyn and London sales dries up they will have a much leaner org to finance.
They will continue to turn a profit where they can from selling K.Halls and Assembly Halls, but one day they will find that the whole thing is cash strapped.
They will then have to rely on increased donations, which is not a guaranteed level of income.
As they lose members, as the Abuse Scandal gets through to the R&F, I can see donations going down and down.
The future is not rosy for JW Org, nor should it be, they are way past there sell by date.