With the caveat that I haven't looked in a while, the rot seemed very anglo-specific. Coming over from Germany almost three decades ago, it was amazing how much US text books just didn't cover.

There were a few developments in Germany that pointed in the same direction, but there a large gap at the time. Meanwhile, even back then, eastern Europe certainly had even higher standards. (I replaced a lot of math textbooks with a copy of Bronshtein & Semendyayev)