Vin Scully probably spent much of his youth doing telegraphic re-creations on a tin-can-and-string network in his bedroom. I'm sure he practiced just as long and hard on his announcing skills as Don Drysdale did on his curveball.
It's no accident that world-class announcers (Scully, Allen, Caray, Harwell, Barber) spent their careers behind the mike while ex-jocks didn't think about broadcasting until they lost a couple of feet off their fastball or home runs became warning-track outs. As surely as there are future major league players in the minors, there are future Vin Scullys and Harry Carays honing their craft from Bakersfield to Pawtucket. They'll never get the chance at this rate.