The launch of the iPhone Air as the first eSIM-supported smartphone sold in China marks a pivotal moment in the country’s telecoms history, as state-owned mobile carriers vie for dominance in a changing landscape. Beijing approved “commercial trials” of the handset’s eSIM function by the country’s “Big Three” telecoms operators – China Unicom, China Mobile and China Telecom – last week, and the iPhone Air sold out within minutes of its release on Friday. Domestic brands quickly followed suit....