This is in comparison to the delivery center methodology by e commerce where the land use for delivery driver is somewhere further away from what is needed for community events, and every delivery truck is filled to the brim, way more full than what each consumer vehicle would be filled up with?

Big trucks filled with stuff delivering a few things to each of many places is less efficient than personal cars delivering big loads with lots of things to one place.

Your SUV with a Costco haul is probably driving less distance per person and carrying MORE per person while being a smaller more efficient vehicle.

Amortizing fuel per item or distance per item I'm betting the personal vehicle wins while also being better able to deliver perishable/frozen items.

(also the likes of Amazon are terrible to employees in order to make margin while Costco is the opposite)