Retouching is an art. To the pro, this is just another tool to increase efficiency. You pay them not just for knowing how to use Photoshop, but for exercising good judgement. That said, I imagine this will shrink the field, since fewer retouchers will be able to do the same work, unless the amount of work goes up commensurately. Will people get more retouching done if the price goes down? Not sure.