You're exactly correct. There is no need for new math books - except that the teachers want to foist a new pedagogy on their poor students.

You can pick up any calculus book from over 100 years ago and learn calculus from it - same for trig, same for geometry, etc. There is no need for new books or new methods to teach math.

What this all ultimately comes down to is this: The educational bureaucrats cannot admit in public that the reason why black and hispanic students lag in grades and test scores is their home life. There is a reason why students from Asian families succeed in math -  their families. The difference between levels of educational attainment cannot be fixed with spending tax money. 

This central truth infuriates the "multi-culturalists" - not all cultures are equal. Not all cultures will have equal outcomes.