The best thing about two companies vying to be the biggest electric-vehicle maker is that there is any competition at all. For years Tesla was by far the dominant manufacturer of zero-emissions cars, despite all the claims from Ford Motor to General Motors and Volkswagen that they would soon be worthy competitors. These legacy players are still largely struggling. But another upstart has sped ahead, with China’s BYD ,on Tuesday unveiling sales that allowed it to overtake Elon Musk’s outfit for the final three months of 2023. From an industry perspective, though, who’s on top is largely irrelevant for now.