Capacity is the appropriate metric when talking about what we could do.

Actual production figures are what determines the supply of batteries available, not what the factories hypothetically could produce if they had unlimited inputs. Your factory could make 1000 GWh of batteries per year, but if you only have enough input materials to build 500 GWh then that extra capacity is useless.

Sure, if we're talking about 2024. My comment was about the next couple of decades.