Anduril, the defense-technology startup Luckey founded in 2017 after his politically charged departure from Facebook, could be set for a $60 billion valuation. The company is riding a record surge in global defense spending and a shift in Silicon Valley sentiment toward working with the military, selling autonomous systems such as its Fury drone and Ghost Shark submarine to U.S. partners including Australia, Japan, South Korea, and Taiwan. War in the Middle East—between high-tech planes on the side of the U.S. and Israel, and relatively low-tech drones and missiles on the side of Iran—is also revealing how current-day warfare is...