I don't know. Perhaps they are still at the "convince someone to actually try it for an entire n-year math curriculum" stage? It's not like using Tau is somethi

I don't know. Perhaps they are still at the "convince someone to actually try it for an entire n-year math curriculum" stage? It's not like using Tau is something that you can do in class for a week and expect better results. Even if you try the lesser "here's tau, always substitute 2pi with tau" every couple years on a group of students and track them through their math learning, it takes time and a lot of effort to get those numbers. In the mean time, there is lots of anecdotal evidence of people understanding a lot of concepts easier with it, suggesting these studies be done in a scientific way.