There is a ~~solid state~~ sodium battery factory being built in Japan, I think, and one in America. (Yes, I mixed up my two battery technologies, a common problem in a stagnant field...) But yes, real life isn't a game, you can't immediately use new tech as soon as it becomes viable, and factories take time to build. That doesn't mean that advances haven't been constantly occurring, just like advances continued to occur with NiMH battery technology a decade after lithium was mainstream. Partly, no doubt, because factories are expensive, they take time to build, and companies like to maximize the profits from their investments.