Seven of the 10 bestselling cars in China in June came with a plug. Tesla’s Model Y crossover SUV has comfortably outsold every competitor since February, while BYD’s Dolphin hatchback has already overtaken established competitors just months after deliveries began. That’s come on the back of a price war, instigated by Tesla, so savage that the government last month induced automakers to sign a pact pledging to compete fairly and refrain from “abnormal pricing”. (The latter commitment was retracted two days later.) There’s no question that the fight for market share has been damaging. First-half auto sales in China have...