I totally agree with the rest of your post, but this part I'm not so sure about.
I think Disney LOVES renting out declared
DVC rooms for cash. As far as the room itself, if a member stays in the room, Disney gets the original purchase price of the points, and the annual dues. If Disney rents that room for cash, they get the original purchase price of the points, the annual dues, PLUS the cash paid for the rental.
With regard to dining and merchandise, I wouldn't be surprised if a cash renter who is reserving a room within 60 days of arrival is less likely to be cooking as many meals in the room as a member might (more likely to be someone who would normally be looking at hotel rooms and dining out 100% of the time), and is also likely spending more on merchandise than a member (I know we don't leave every trip with armfuls of Disney stuff, or at least not as much as a less-frequent visitor). Sure, there are likely people from across the whole gamut, but I'm guessing cash renters might spend more on food and merchandise on average.