My first shot of the year, usually sometime in August, is often within 1/2" of where I'm aiming...then it goes down from there.
Certainly possible to be a one shot wonder , but not the norm. Maybe the guy's like the Michael Jordan of bow hunting? I've had my sights need to be re-tuned, all kinds of stuff to check up on before sticking the big one. A lot of it has to do with muscle memory. The new bows are incredibly easy to shoot, but you need to be able to draw, aim, and fire without thinking about anything except that hair you want to hit. Kudos to this guy if he can do it year in and year out with one shot, but a big part of the pleasure for me is in the preparation.