Access to weight rooms at an early age, case in point -
You see that big muthafukka on the right, he's 15 in that pic.
And he wouldn't be able to play football at high level because he's too buff. This dude is predestined to be US football players and that's why they are built that way because that's how US football players are.
Passing, shooting and vision don't require bodybuilder morphologies. You seem to know the game so I won't question you but you are missing the point. Producing great athletes doesn't mean that you will produce great football players not because you can't be a great player being a great athlete but because you need to be a good player first. This breh is an elite athlete because being a defensive linesman requires it ! This body type is the most efficient as his position and if he was skinny, nobody would ever think of playing him as this position. Same with running backs. But a QB doesn't need to be brolic like him.
But look at the MLS players. There are no american players built like this because you don't need it to play the game at high level. Hell, I will even say that being like the breh is a setback to be a great player. Explosiveness is good but you forget the importance of the ball and its handling and above all, endurance. This breh, wouldn't last in a B-Ball match. 20 minutes and he's coughing his lungs. This breh, would be useless in a baseball match
This breh would be VERY interesting in rugby to play as a winger because his body type fits the position but this breh will never be top of his town in tennis and so on.
I respect your opinion as you are a very knowledgeable breh sports-wise but you value athletic performances way too much. In football there are not necessary. You ever play footy with brehs like this ? Good in contact (obviously), 1 and 1, fast on the ball, dominant.
But them brehs always play as defenders because they clumsy, can't make a proper pass, tire quickly and lack vision. Obviously there are exceptions but it's that way usually.