As far as GD's method to their madness, what I think they are doing is listing the original architect(s) and then whomever completed the most recent renovation or restoration work. As it has been pointed out before, the impact made by each of those reno/restos is widely variable.
Separately, I've been trying to come up with a decent analogy to the golf course design hierarchy, and my first thought was that of a football team, where a head coach is the architect, coordinators and assistants are the various field supervisors and associates, the skill players are the shapers, and other players are the additional important component labor pieces implementing the thing. Shapers and laborers will never be as popularly regarded as players though, and while football coaches can't get in on the "action," golf architects can and do, jumping on bulldozers to shape greens. Their "coordinators" especially jump in on the action with associates running jobs while also building a majority of greens, bunkers, and other important pieces.
All teams (football or golf design) are different with different philosophies, both in style and approach. Some adhere more strictly to the hierarchical chain while others blur the lines a bit more. It all starts though with the head coach (architect) and their system. You can have all the talent in the world at your disposal, but it tends not to matter too much if the head coach can't direct and corral it all. Conversely, a great coach/architect may not be able to get the results they want if they don't have the requisite talent in place. Successful golf design is very much the result of the work of many important people, but it all eventually falls back to the person on top.