The reason why you see it happen on the pro tour more than on the public course is because of the amazing spin that pros put on the ball. With a huge amount of back spin and a soft covered golf ball (most hackers use very hard shelled golf balls) a high trajectory shot can "grab" either the pin or the side of the cup and not pop out.
Edit: i mean why you see the ball stay in the cup, not why you see more aces. Obviously the pros are much better than joe hacker.