I 100% agree with SBF. The general public hasn't been the customer of the WTS publishing machine for decades. The customer probably since at least the 40s if not earlier has ALWAYS been rank & file JWs. Think about the magazines for example.
Family of 4 need a subscription or copy of the old WT rag which included articles "for the public" as well as study articles. Plus the pressure to also at least get a personal copy of Awake. So that's 16 mags per month (back when they did each semimonthly). That same family maybe placed say 8 each so 32. But, if you add in all the books bibles and other items that were rarely sold to the public (at least I rarely placed them but maybe I was just bad), the placements to the public were a small piece of the puzzle. And the least expensive item to produce as well as the item with the lowest cost tag.
Dropping the sale of the literature all of the sudden made their income variable and dependent on voluntary donations from JWs. Not many people I've seen have actually tried to get a donation from the public and those that ask often don't receive. And we know JWs are not that generous nor do many have a ton of disposable income (across the globe).
You go from knowing you're going to get a set amount based on past consumption to just hoping someone donates and you end up exactly where they are.
If they kept the sales portion and paid taxes, I really don't think the average JW would have reduced their standing orders. Maybe some would have, but I don't believe it would have been significant. Also, they would have still bought the higher margin (assuming) items such as books, bibles, videos, whatever. Likely at the same rate since you would only be adding a few percentage points to the overall cost.
The reason they had releases every year at the conventions was to sell books. It took them too long to realize they couldn't get the same returns so they cut down on the quality first (paperback books) then moved to online at the same time reducing the quantity. No sense in publishing items that you can't make money on.
I think it's pretty evident that JWs are not donating at the same rate that they previously purchased. So while some double dipping takes place, it's difficult to believe that it's significant. Certainly not what they expected but because they have no real business sense, their expectations were not grounded in reality.
I guess they could drop the requirement without the foresight of what it will do to morale. It's just odd to me that they would do that. I could see them doing other things to save money before stopping to micromanage people at the local level. I believe others have mentioned that the individual reports never go to the WTS, what is reported is the aggregate activity of each congregation (former secretary here).