How often in sport, do you see the team that starts off like a train, usually run out of steam by the end. Also, a team that starts poorly, slowly gets better and then peaks at the right time. Australia certainly did that.
England didn't drop off by much, but enough not to be at their best. They certainly missed Mills, if he had played maybe things might have turned out differently, but certainly, they need to sort out this situation whereby you win the toss you win the game.