A goal now often ends with a dozen substitutes arriving before the teammates on the field do. The scene looks unplanned and is frequently anything but.
The bench arrives first because it is closer and fresher
Substitutes stand near the halfway line with legs that have not run for an hour. A scorer celebrating in the corner is a short sprint away.
Teammates on the field are scattered across a hundred yards and have just finished the attack, so they arrive second by simple geometry.
That gap is what creates the picture of the scorer surrounded by players in bibs, which is a distinctive image of the modern game.
Coaches use it to bind a squad that mostly does not play
Only a fraction of a roster starts, and the rest spend a season watching. Squad morale is one of the harder management problems in professional soccer.
Encouraging the bench into celebrations gives non-playing members a role in the emotional life of the team rather than only in training.
Managers who talk publicly about squad unity are often describing exactly this, and the corner-flag scrum is the visible evidence they point to.
Rehearsed routines need bodies, and the bench supplies them
Choreographed celebrations that involve several players are difficult to organize among ten teammates spread across the field at the moment of a goal.
Substitutes can be positioned, briefed and available, which makes them the practical cast for anything more elaborate than a hug.
Where a routine has clearly been planned, the participants are usually the ones who were standing together on the touchline when the ball went in.
There are disciplinary limits and teams know them
Officials treat the technical area as a controlled zone, and staff members leaving it during a celebration can draw a caution.
Substitutes entering the field of play are subject to their own restrictions, and repeated mass celebrations can bring a warning to the coaching staff.
Well-drilled squads therefore run a version that keeps staff behind the line, which is why you often see coaches jumping in place rather than joining the pile.
Broadcasters have adjusted their camera plans around it
Directors covering American matches now hold a wide shot longer after a goal, because the bench arriving is a reliable second beat after the scorer's reaction.
That extra shot buys time before the replay and gives the sequence a rhythm: the finish, the scorer, the crowd, then the flood of substitutes.
Teams aware of the coverage put more thought into what that second beat looks like, which is how a spontaneous burst became a planned one.