If we're going by the 10,000 hour rule, mathematically speaking, I suppose the snapper would end up with the most filing cabinets of duds, but just as many successful images as a slow and methodical photographer. That's if we're ignoring subjectivity and only go by what the curators tell us are the great images. But I think how many photographs we need to make is entirely dependent on the temperament of the photographer and type of photography they pursue... then add luck and being there!
I think the 'shoot and hope' approach is definitely more true of photojournalists and if you look at the Magnum Contact Sheets book, it becomes clear how integral trial and error and editing are to this process. A landscape photographer may come away from a shoot with a couple of 5x4 negatives, having spent an hour composing each. His approach then depends more on clear visualisation at the shooting stage than spending hours editing post-shoot. In my mind the negative count:successes ratio is much closer with landscape photography, if your temperament and working method is suited (which means you would work more efficiently). Regardless of ability and success, I think any photojournalist would have more negatives than even the most prolific landscape photographer.
If success in photography was totally dependent on how many images we made however, surely we could all be rich stock photographers with a bit of simple hard work?