From listening to that podcast Jason Dodd and another coach did ages ago we start players in the youngest age in games as 1v1 then 2v2 and 3v3 and slowly building up through ages. This encourages technique, comfort on the ball and versatility but maybe isn't the best way to encourage the features of potentially good to great goalkeepers.
And even then he was first choice at his previous club and in the England set-up (not main squad) The reason he became good was having to throw oranges across the room he shared with John Burridge on away trips.