Fad driven, or politics/corruption driven? The textbook "industry" is one of the most pernicious, that really should be put out of business... in today's world, even if we were doing dead-tree based knowledge devices, they could be tailored to the individual and printed on demand.
Of course, things like tablet-based (eInk or LCD) reading and khan academy are the future of learning.
There's two separate phenomenon. Pedagogical approaches follow fads rather than solid principles known to work. Textbook selection is corrupt. Both are problems that have not been solved at least since Feynman's experience in the 1960s despite much effort and an awareness of the problem.
Of course, things like tablet-based (eInk or LCD) reading and khan academy are the future of learning.