The cash inventory for DVC accommodations is completely separate from the points inventory. It is not at all unusual to see no availability for points while availability still remains cash (and the reverse).
Cash rooms come from 3 sources:
1. The largest percentage of DVC accommodations that are available to the general public for cash come from members who use their DVC points for a non-DVC option. For example, to cruise on the
DCL, to stay at one of the resorts in the Concierge Collection or the Disney Collection (like the GF or Poly) or for one of the "adventures" in the Adventurer's Collections. DVC sends the equivalent number of room nights to CRO and uses the proceeds (minus a commission for CRO) to pay for the member's trade. So for the most part, the number of rooms in the cash inventory reflects the number of of members who are using their points for something other than a stay at a DVC resorts or an exchange via II.
2. A small percentage of each resort (2-4%) is retained by Disney. If the rooms represented by that percentage aren't need for administrative reasons, they too can be rented to the public.
3. Some rooms / points are owned by the Developer. These rooms are ready for occupancy but not yet declared into the condominium. Until they are needed for sales (the developer has to keep enough rooms in inventory to cover sales), the developer makes the rooms available for rental to the general public. The proceeds of the rentals (minus CRO's commission) are returned to the Developer.
A rather long explanation - hope it answered the question.