Drawing on innovation chain analytical framework and institutional logic theory, this research provides a theoretical analysis of the mechanisms underlying innovation-chain fragmentation in key core technology development and, on this basis, explores the mechanisms through which the new system for mobilizing resources nationwide supports end-to-end breakthroughs in key core technologies. The study finds that key core technology development is embedded in institutional complexity, where state logic, scientific logic, and market logic coexist and interact, and innovation-chain fragmentation is a concentrated manifestation of the coordination difficulties generated by such institutional complexity across different stages of innovation. It further finds that an enabling government, through institutional coupling, field construction, and actor orchestration, establishes the mechanisms that support innovation-chain integration, promotes effective linkages among basic research, applied research, and market diffusion, and ultimately provides end-to-end support for breakthroughs in key core technologies.