Comprehensive look at the complexities and economic viability of last-mile delivery, focusing heavily on e-grocery logistics and the global comparison of autonomous vehicle (AV) adoption between the US and China. One key theme is the critical importance of delivery experience for customer loyalty, despite last-mile logistics currently posing a significant challenge to retailer profitability due to high costs, which retailers often subsidise. The sources stress that adopting advanced technologies like real-time route planning, AI, and warehouse automation is essential for retailers to meet consumer demands for faster, more frequent, and flexible delivery options without eroding profit margins. Furthermore, the analysis highlights that China is achieving faster and more efficient scaling of autonomous delivery systems compared to the US, primarily due to stronger government support and unified regulatory environments, offering a model for US policymakers and businesses.