In isolation this statement is true, but thats only part of the picture when talking about multispeed bikes. Look at the friction facts graph. 53x28 has higher friction losses(=increase wear) than 39x21 for ~ the same ratio. Side loading introduces its own wear patterns. Its also why many triathletes use larger chainrings, not because they can turn a 56x11, but so that their desired gear is in the middle of the cassette.