Where have I ever claimed that people buy the books just for the tech? My argument is that not many would do so.
There are sourcebooks, supplements, and adventures I have absolutely no interest in. If I were still rich enough I may get them for collector purchases, but I am now of the age when I am contemplating everything I own going in the skip once my daughter has to clear the house, so I only buy what I am interested in. I will therefor not spend £40 on a book that only has 3 pages that are of interest to me.