"I dont have to prove that [I was right]," Van Gaal said. "Why do I have to prove that? I have already said what I think he was not a line-up player, he was more a substitute than a line-up player.
"He was already, with different coaches, not a line-up player, but then with Mr Van Gaal, the world is changing? No, the world is not changing. They are the facts. They are not my facts, they are the facts of Danny Welbeck and we have [Robin] Van Persie and we had Wilson, and when you keep Welbeck, then you dont give any chance to youngsters and that is our philosophy.
"And then also we could buy Falcao. When that is not enough reason then I dont know what is then Im not a very good manager."
While Van Gaal conceded that Welbeck has benefited from the opportunity afforded to him by Wenger, the United manager insists it is too early to judge whether he was right or wrong to let him leave.
"For Welbeck, it was a very good decision because as a line-up player, he develops himself much more," Van Gaal said. "And if it was the right decision for Manchester United, it is dependable on how we play, how we score and in what position we shall finish in the league.
"But after that you cannot say it is a very good decision or not because we are in another process to Arsenal. They have a manager who has been there for 18 years and the playing style in 18 years is the same, so that is very different. Here, Welbeck doesnt play every match. Mostly he doesnt play."
