It appears that most of the substantive information in the Insight volumes is lifted directly from its predecessor; my questions: what accounts for its immense increase in size? (I don't have the stamina or patience to make the comparision) I suspect that one reason for it was to distance its content from the main authors of the Aid book, i.e. Ray Franz, Ed Dunlap and several others who defected in the 1980s, as their contributions to the latter became more or less general knowledge in WT circles.
Aid Book Vs. Insight On The Scriptures: Compare and Contrast, Anyone?
what accounts for its immense increase in size?
Bigger font and photographs, mostly. Also the paper is a bit thicker - as I recall the Aid book used the ultra-thin "Bible" paper.
It certainly isn't any increase in "scholarly" writing!