During the 60s, people in the US (and also in Europe), school curricula introduces [New Math](http://en.wikipedia.org/wiki/New_Math) where students began with set theory in the first grade before learning to perform addition or multiplication. 

Somehow, this has ended. **Can you explain why?** 

(Of course, in the linked article there is some criticism, but almost everything the government does is criticized and politics don't really care. Why did they care here?)