I believe logistics has become a weakness for Amazon. Other retailers seem to handle most of their warehousing and logistics on their own (?). Amazon reduced the need for warehousing but seemed to have become totally dependent on other companies for logistics. For long time they benefited from tax breaks and users willingness to wait few days for packages to get delivered. With price matching offered by several other retail stores, and Amazon thinking of starting their own retail stores, it makes sense to invest in their own logistics as well. I guess they would like to differentiate themselves in the long run as a ship-to-door retail company with excellent customer experience.