Perhaps more than any other consumer-packaged-goods form factor, the beverage category has a tendency to follow trends. The once-fringe sparkling water brand LaCroix capitalized on a trend away from sugary drinks by leaning into a kitschy “anti-Perrier” aesthetic and unorthodox flavors like Lemoncello and Cherry Blossom. LaCroix’s sudden surge in popularity opened the flavored seltzer category, which promptly became...