Well, now that I think about it, a big factor on the older holes is that a lot of them [12-13 Augusta, 17 St. Andrews, etc] have been prominently featured in tournament play, and that creates special attention on them. But I do think some of it is laziness, or to be more charitable, fear of bucking the consensus choices.
Some of the holes on the new list seem to be there because they mirror the reputation of famous old holes -- the 16th at Cabot Cliffs piggybacks off the 16th at Cypress [even though they are quite different], and the same goes for the Little Devil at Barnbougle as a mirror of the Postage Stamp at Royal Troon.