Inspection is expected. In the transport industry, all sorts of parts need regular inspection. Batteries are different. Performance loss over time leading to replacement decisions is unussual. Virtually no other part degrades in performance the moment you use it. Lots of parts have time limits, especially in aerospace, but few degrade. Those running fleets see this as unussual and unpredictable which, at scale, means extra expense. A tank that needs inspection every decade is a known problem. A battery that looses 1% to 5% capacity every year, depending on weather/use factors, is harder math.