The growing demand for photovoltaic (PV) technologies that are lightweight and flexible and can be integrated seamlessly into diverse applications has propelled interest in thin-film solar cells. Among these, Cu (In,Ga)(S,Se)2 (CIGS) and metal halide perovskites have garnered significant attention in the past and present, respectively. Although CIGS reached commercial readiness after decades of refinement, its large-scale deployment was hindered by manufacturing complexity, scale-up challenges and a lack of coordination between materials, device design and production systems. Despite setting record efficiencies at unprecedented pace perovskite solar cells now face similar challenges on their path to commercialization: ensuring long-term stability; translating laboratory performance to scalable architectures; and aligning with industrial realities. Here we revisit the CIGS experience not as a benchmark, but as a blueprint, highlighting how its successes and failures can inform a more deliberate and durable trajectory for perovskite PV. By bridging this historical perspective with the current frontier, we propose that the future of perovskites depends not only on continued innovation, but also on learning from past thin-film PV experiences to avoid repeating their pitfalls.