The title of this post makes an unsafe assumption, specifically that many in sales are prepared for the expected, they are not. Given the surprise and outrage many sellers display when they get the most common objection while prospecting, or the slightest push back throughout the sale, suggests that they are not prepared for many predictable elements of their sale.
For many preparing for the expected seems counter intuitive. But practicing things you will likely face and execute in every sale, be it weekly role plays, or rehearsing on your own, just trains the muscle, and sharpens the nerve. Role playing an hour a week, and visualising each sales meeting before you show up, will give you a number of advantages. Not only does it bring you closer to the 10,000 hours of experience it takes to be a phenom or expert, but the more you master the core elements of a craft or skill, the more bandwidth and focus you have for things beyond the core. There is no reason sales people should not practice as much between calls, as they expect their favourite ball player to practice between games.