<p>Perovskite photovoltaics present great promise for next-generation solar energy, yet their commercialization is hindered by a critical scalability-stability gap, where the distinct fluid dynamics and crystallization kinetics of scalable solution-processed coating methods produce varied film morphologies and unstable degradation behaviors. Herein, we address this challenge by re-examining stability through the exclusive lens of scalable solution-based fabrication. The degradation mechanisms in scalable processing are dissected, highlighting the critical role of precursor ink design, where solute purity, ink aging, and solvent engineering collectively govern film uniformity and reproducibility. The exacerbation of intrinsic instabilities under scalable processing is analyzed through crystal and compositional design, defect generation and passivation, and ion migration in large-area devices. Stable device architectures suitable for scalable manufacturing are explored, including comparisons between n-i-p and p-i-n configurations and advancements in charge transport layers. Encapsulation is critically evaluated as the ultimate barrier for commercial modules, covering scalable techniques and material selections, along with an assessment of operational stability under real-world environments including moisture ingress, thermal cycling, and UV-induced degradation. By integrating these insights, this review establishes a holistic framework for the co-design of process scalability and operational longevity, outlining a coherent pathway toward durable and commercially viable perovskite solar modules.</p>