Why are South Korean football fans choosing European clubs over the K League?

Yoon Jin-woo had never gone to Seoul World Cup Stadium to watch FC Seoul, the city’s team and the club that calls South Korean football’s symbolic home its own. But on Sunday night, he made the pilgrimage from the suburbs of Gimpo to see Manchester City and Atletico Madrid, two European clubs whose pull in South Korea rivals, and often overwhelms, interest in the domestic game. The 21-year-old and his friends were among 50,000 fans who filled the stadium with City’s light blue and Atletico’s...