The U.S., Japan, Taiwan, the E.U., South Korea, China and India are shoveling hundreds of billions into chip plants and “semiconductor independence” — as if national security came in fab-shaped boxes.

How thin can a foldable phone get before physics says “no”? Samsung’s new Galaxy Z TriFold pushes that limit, with a profile of just 3.9 millimeters at its thinnest panel despite packing two hinges, ...