Model-Based Systems Engineering (MBSE) has made substantial progress in managing system complexity, yet it still lacks principled support for understanding system behavior during early design. SysML v2 introduces a richer semantics for modeling behavior, but its utility remains limited by a lack of executable semantics, weak interoperability, and the absence of native support for formal verification and design-space exploration. We argue that a paradigm shift is needed, one in which behavioral models become first-class, executable artifacts, navigable within a dynamic design multiverse. This position paper presents the vision for the Living SysML v2 Blueprint, a next-generation SysML v2 virtual machine that unifies dynamic execution, multiverse exploration, and native formal verification. Central to this vision is the Transparent Execution, Observation, and Control (TEOC) API, enabling accurate semantic inspection and tool interoperability without model transformation. By tolerating incomplete models and exposing structured execution traces, the LivingBlueprint VM empowers system engineers, verification experts, and business strategists to engage with design decisions iteratively, rigorously, and early. This architecture redefines the semantics–verification–execution triad at the heart of MBSE, offering new foundations for explainability, trust, and AI-augmented design. This paper outlines the theoretical pillars, practical challenges, and community-wide opportunities of this approach and invites collaborative efforts toward a new class of MBSE platforms centered around behavioral fidelity and multiverse awareness.