Value. They might supply the 24-70/4 in a equipment for an efficient worth of round $500-600 and nonetheless become profitable on it. That may not be potential with the brand new lens.
Generally, if you cannot determine why a digital camera firm has accomplished one thing, the reply is usually worth. By way of what drives gross sales, the three most vital elements in a digital camera or lens are: worth, additionally worth, and at last, worth.
That is true for the overwhelming majority of client merchandise.