The printing business not profitable any more with the advent of the internet and paperless information. So it would be very unwise for these CEOs running the watchtower corp. to keep throw money into shitty literature publications in print to get donations. They were moving very heavily into property investments capitalizing on free labor but that seems to be on the skids these days with many unfinished buildings and perhaps lack of duped volunteers offering themselves willingly at their own expense.
Cart witnessing seems to be a total failure especially with all the bad publicity they are getting on the internet with more and more lawsuits knocking on their door. So I would imagine the WT corp. will try some other way to generate funds before they go belly up. I think door to door preaching will eventually fade to nothing in a few short years with the GB and other key members retiring to some chemical dump property away from public eyes trying different cons to keep afloat financially.