Because Soviet math textbooks target a different audience: those kids who really enjoy math and derive pleasure in a bit of complexity (think Sheldon Cooper fro

Because Soviet math textbooks target a different audience: those kids who really enjoy math and derive pleasure in a bit of complexity (think Sheldon Cooper from BBT). You can call them elitist. Nobody cares about the other kids. US textbooks, on the other hand, are targeted towards more general audience--the average student. That doesn't make them bad, just different.