No matter who wins, the blockbuster antitrust trial pitting AT&T against the U.S. government will reshape the media landscape. What it won’t do is end the upheaval of an industry contending with new competitors and new technologies.
Beginning on Monday, AT&T will defend its $85 billion acquisition of Time Warner in federal court. Investors in companies from pay-TV distributors like Verizon and Charter to content creators like Disney and 21st Century Fox to tech firms like Netflix, Amazon and Google should pay close...