That's not what I mean. Picking a box isn't so hard (although box packing algorithms for non-uniform objects is still tricky).

The robotics part is more like "how do I make a robot that can pick up a pen, a 50kg weight, and a silk blouse, and make it put all three in the same package without messing up?" In a factory that would be three distinct robots because that variability in weight, size, surface friction, malleability, etc makes it a hard problem. In a warehouse it would need to be one robot. Even if you compromise and accept additional packaging like putting soft items in boxes or bags it's still quite difficult.