City Football Group owns 13 clubs across five continents. Red Bull operates a network spanning Austria, Germany, Brazil, and the United States. Eagle Football Group speedran four acquisitions in 18 months. Either these billionaires have cracked a code the rest of football missed, or they're all making the same expensive mistake.   Over the past decade, multi-club ownership (MCO) has exploded from a curiosity into an industry phenomenon. What started with ENIC's dabbling in th