It's the TL;DR syndrome. I hazard to guess that as DSLRs are becoming more affordable into the realm of becoming a consumer product, folks would treat it like any other modern consumer product. Expected to work out of the box and somewhat simple to operate, like an iPhone. Coupled with attention spans getting shorter, reading the manual is perceived as optional. Why bother with Walls of Texts from the manual or guide when asking is deemed faster & easier, regardless how thick or simplified the printed info is? As evidenced by the number of users using Auto mode, or even P mode if they are feeling adventurous!