Why do all the world’s best athletes do Subway commercials?

Close your eyes and imagine the last time you were inside a Subway. Do you see the dated storefront? The fluorescent lighting? Do you catch a whiff of that unmistakable, disturbingly sweet bread smell? Maybe there’s a group of high school kids snarfing down their subs after school. Yet, this is the very same chain that has, in recent years, attracted some of the world’s biggest and highly-coveted athletes to playfully hawk its sandwiches in a barrage of TV ads: Tom Brady, Steph Curry, Serena Williams...