At 2000kg, you're storing two tonnes of fodder in a single unit — a scale that's typically reached by large commercial dairies or cooperative collection points consolidating fodder for multiple herds. The engineering demands step up meaningfully at this size: seam strength and material thickness both need to hold under the weight and pressure of two tonnes of packed silage without stress failure, which is a different manufacturing consideration than simply making a smaller bag bigger.
Farms and cooperatives choosing this size over multiple 1000kg bags are usually optimizing for fewer total units to manage — less labor spent packing, sealing, and monitoring individual bags — provided they have the operational capacity to work through that much fodder from one opened bag before spoilage risk from air exposure becomes a concern.