This is somewhat an unfounded theory of mine and I was hoping if anyone has any insight: but I sense that this is perhaps a construction of Western restoration/preservationist theory. A lot of effort seems to be taken to either preserve original material, not take liberties etc. While touring temples and museums in Japan, I got a sense that restorations were much more aggressive, and less regard was taken to the preservation of material (or building "fabric"), with a greater focus on the use of traditional techniques during restoration.