I think the OP by respectful_observer could be right on the mark. The accountants at HQ want steady cash flow coming in, not random contributions, and they've really already started doing a "lite" version of this in the US. Last year they had congregations to take what were essentially pledges from members. The congregations then informed the branch of the total pledges for their congregation and were strongly encouraged to contribute that amount to the branch each month. Because they were anonymous pledges by the members, the total added up to much more than would be realistically donated. So congregations have struggled to try to fulfill their pledge. How is the shortfall met? I would venture that in most congregations there are a few families that have some money, and some of those families have someone serving as an elder. It's those families who make up the slack.
The only change in scenario between what is happening now and the OP's scenario is that congregations will be told how much to contribute for each publisher. That could happen any day now.