What Makes a Shōnen Juggernaut?

The Shōnen manga formula goes something like this: take relatable underdog characters marketed towards teenage boys, add melodramatic themes of friendship, loyalty, loss, and struggle plus some cool fights, and sprinkle with redemption arcs, coming-of-age conflicts, and character deaths to taste. What makes certain titles iconic or commercially successful? How do Shōnen stories distinguish themselves from Western coming-of-age narratives like Harry Potter or A Wrinkle in Time?