For me it's less the reading and more the multitasking, especially in 3 dimensional spaces. I had one of those magazine sized guides for Myst, and as a point-and-click, it was simple enough to navigate. But reading along with a guide, putting it down, playing, looking again, only to realize I got turned around and went to the left instead of right 3 steps ago is what got confusing. (Having a desktop in another room that i had to get up and walk over to probably didn't help either.) You're right though, modern guides pale in comparison to the level of detail in those old guides.