There are three different thread topics going on here at once:
a) Pine Valley
b) The makeup of the top 10
c) Groupthink
It's hard to comment on one without thread-jacking the other, but I will try to sort through them.
a) Is PV destined to always stay #1 ? Probably, with the panel we have. If we had a bunch of women golfers or 20-handicaps or people who didn't care about history, it certainly wouldn't be #1, because they'd find it much too difficult. But then their opinions would be dismissed. That isn't so much groupthink of one panel, as groupthink of good golfers generally, that if you don't think Pine Valley is great, your opinion is meaningless. [Note: Pine Valley is a 10 in The Confidential Guide and has always been one.]
b) Back when we first started ranking the courses in order, my one argument in favor of doing so was that there was no more difference between 10th and 11th place, than between 9th and 10th, so listing the courses in groups of ten [as GOLF DIGEST used to do] exaggerated the importance of a course moving up or down. Augusta, Pebble Beach, and LACC are 9's in The Confidential Guide [and I think they always have been], so to me they're all about even, and if there's only room for two of them in the top ten and the other is eleventh, I don't see it as a big deal at all.
c) However, the system doesn't allow me to vote all the 9's the same. I have to vote for a top three, and a top ten, and then for 11-25, as if the divisions were that precise. My rule is never to change my vote on a course if I haven't gone back and changed my mind about it, but if I see a new course this year and think it belongs in the top ten, the voting system forces me to push one course off the side and down to "11-25", even if I don't think anything about it has changed. That is the point where groupthink comes into play, and people start looking for rationalizations why it should be Pebble instead of Augusta that's voted off the island.