I was stationed in Spain from 68-72..and I think it was 1971, the Harlem Globetrotters came to Barcelona for an exhibition game. It was outdoors, at the Plaza Cataluna..just unreal..I was with a couple of Marine NCOs who were both tall and black...people kept on stopping us and asking for autographs..I signed easily over a hundred....they shut it down, and built an elevated court..I think that the crowd was estimated at 50,000 when the stopped trying to count..I realized then that the NBA/American basketball had a global appeal..
NFL stars, and NFL games, seem to have solid international appeal. The “American Bowl” series (NFL games played internationally) has been a raving success, for a long time a pre-season game played in Mexico City was the highest attended NFL game ever. But even pre-season games feature real NFL stars taking a couple of snaps. NFL Europe didn’t do that, a few of the players made it to the NFL proper, but most of them landed 3rd or 4th on the depth chart. Nobody went to Europe a star, nobody left Europe to become a star. Which is why it failed, while real NFL games in Europe do quite well, getting 2 next season.