I will have to go back and read other comments as I am sure there are great insights here.
As far as my understanding goes, Watchtower was a giant printing corporation. They sold literature. Their conventions were huge sales seminars for their unpaid sales force, who also happened to be big customers. So they were like Avon or Amway in that the customers went out and sold the product, but they had a huge advantage in that it wasn't a pyramid. The sales force were not taking a cut. I am sure it was awesome.
1975 was a huge push to sell more and pay for the modernization of the printing company. It worked no matter what happened to the membership when the end didn't come. And more new members stayed rather than left anyway compared to their slower growth if they didn't have the 1975 campaign.
So the trouble comes from the printing company mentality set in those days lingering today. Selling more literature seemed always to be better for the company than selling less. When they were going to have to pay taxes if they didn't switch to donations, they chose donations. And the slow death of Watchtower started. It was slow because they had modern efficient presses and a volunteer (below minimum wage cost to them) work force. They still made money with their blatant disregard for the laws concerning "donation-only" standards and they told congregations what inflated amounts they SHOULD be paying for the literature.
As time went by, the lawyers told them they couldn't keep insisting on given amounts from congregations for literature. They eventually switched to insisting on given amounts for all other things- C.O. expenses, donations for the worldwide work, yadda yadda. The bulk of the donations in the 1980's switched from nonmember contributions (for literature) to member contributions. If money is chiefly coming straight from hardworking members, then no matter what changes were made over the years, all they were doing was shifting profits from literature to something else- donations at assemblies, donations from the congregations, donations from the buying and selling of properties including Kingdom Halls.
Once you've taken all the money from the congregations and told them they aren't donating enough monthly, all they will do is take their "Worldwide Work" money and money normally dropped in the box at the Assembly Hall and drop it in the local contribution box at the Kingdom Hall to meet the monthly demand. So they just robbed Peter to pay Paul.
The problem would be self correcting if the printing corporation recognized the drying up of money for literature and reduced spending. But it could not reduce it fast enough. There were lawsuits. And there were huge leftover facilities and personnel from the days when they needed that to produce the literature. The facilities are being sold, but in an economy that fetches far less profit than it would have a decade ago. And waiting for the personnel to die wasn't fast enough.
I doubt today's average JW donates as much as members did in previous decades. It's not that they don't want to, but it's just that they don't have it. The mentality of JW's has always been to give time more than money, but they gave what they could. Now, these people who did not go to college and did not accept all the overtime at work and may have turned down jobs that caused them to miss meetings- they just don't have the money to give. The cost of living has risen, taxes have risen, the demands of Watchtower have risen. But the collections are still anonymous and, just like I did at one time, members (rightly so) assume that Jehovah will provide for "His" organization if that is His will, and they give less.
