I think what Schiffy said is the most likely answer. I wonder if they might consider a new package of just the 2-CD Spartacus, not derived from the unlikely scenario of breaking down 1000s of boxsets, but from a new 2-CD or 3-CD package newly produced. I guess this is more wishful thinking on my part as I'd love to buy such a package, but can't justify shelling out $80 or so for the full boxset as it stands.
Whatever the situation, I do hope Varese can offload whatever remains of Spartacus into the hands of those who'd dearly like to have it, but have refrained from purchasing it due to increasing financial burden acting as the primary constraint.