Here is a really good July 1976  Rolling Stone Magazine interview with George Martin in which he’s asked about George Harrison who he says is talented but John and Paul are so enormously talented that it was silly to look elsewhere.But it’s obvious George Harrison was even more talented as a song writer and guitarist than most people realize because in this same interview George Martin says that he didn’t give George much encouragement he just tolerated him. And of course John and Paul didn’t give him much encouragement,so he did mostly everything on his own.