Let me tell you a story.
In 2007 at the Under 20 World Cup, the player that was second best player (best was Aguero) was a dude named Maximiliano Moralez.
In 2011 Under 20 World Cup, Henrique Almeida was the best player.
Two EPL titles.
3 FA Cups
1 Europa League
1 Champions League
Captained his country.
There is no assurance that if he had played under another manager, he would have excelled.