The Milano-Cortina 2026 Winter Olympics present an opportunity to synthesize evolving paradigms in endurance training within the broader context of long-term athlete development. As Olympic winter sports span from endurance-limited events to disciplines in which aerobic fitness primarily serves as a feeder capacity, a single training model is insufficient. In this narrative review, we propose a dual framework: (1) a demand-driven, athlete-centered, data-supported model for Endurance-Limited sports (e.g., cross-country skiing, biathlon) and (2) a Feeder-Function model for sports in which endurance primarily supports recovery, training tolerance, and resilience (e.g., freestyle skiing, snowboarding, sliding sports). Within this framework, we narratively synthesize and critically evaluate the literature across key domains, including individualized volume–intensity architectures, the integration of concurrent strength training, and the strategic use of multimodal stress stacking (e.g., hypoxia, heat). We further address the operationalization of emerging performance constructs such as durability, fatigability, resilience, and repeatability. We also present a heuristic tier framework describing when endurance acts as a primary performance limiter versus a supporting capacity across Olympic winter sports. Subsequently, we examine the role of advanced technologies, from multisensor wearables and analytics to mechanistic approaches (e.g., multiomics), highlighting their potential to shift practice from passive monitoring to active, individualized modeling. Future research priorities include validating field-based operational metrics, defining minimal effective endurance doses for feeder-function sports, and developing interpretable, athlete-centered decision-support tools. By aligning sport-specific demands with individualized, evidence-informed prescription, this dual-framework approach offers a perspective to guide interpretation and future applied work for scientists, coaches, and athletes preparing for Milano-Cortina 2026 and beyond.