The drone in this stunt is operated by YuanTong, a parcel delivery company, not Alibaba. Also Alibaba does not (generally?) maintain distribution centers or hold inventory. So from a strategic perspective drones don't mean to Alibaba what they could to Amazon.
You are right, Alibaba doesn't even sell anything, they are like e-bay, just connect the buyer to the seller. As far as I know Alibaba also doesn't have a delivery service, ShungFeng Express is the most used delivery company. The chinese Amazon is YiHaoDian(360buy), they sell their own things and they have their own delivery operation.
