If they can store 25 exabytes on (55mm)^2 of this material, and they could make (4mm)^2 slices before, why don't they already have 132,000-terabyte storage devi

If they can store 25 exabytes on (55mm)^2 of this material, and they could make (4mm)^2 slices before, why don't they already have 132,000-terabyte storage devices with the smaller size?