Duncan,
The architect has to create a field of play that can accomodate and challenge the very broad spectrum of golfers.
He can't lock himself into crafting a course for a defined "subset"
The solution is to design the best course possible, considering the end user, and to allow for variety in terms of tees, such that all of those defined "subsets" can be accomodated and challenged.
GCGC plays close to 7,000 from the back tees and I don't find playing the back tees particularly burdensome.
Yet, other courses at 6,6,00 to 6,800 are very difficult for me.
One course that I play fairly often has 9 long par 4's and 2 short/medium par 4's.
I find that course to be very difficult, although, all but one of the par 5's are fairly benign.
The problem as Sean alluded to is that the spectrum has widened out.
The disparity has become excessive, ergo, the architect finds himself faced with a dilemma, how to design for that broad spectrum.
More tees, as unpleasant as that may sound, is the answer, unless the golf culture were to revert to where it was centuries ago.