California might have adopted this, but I think the two major states is Wisconsin and Arizona. I do remember last year track had a survey sent to us coaches regarding uniform change. Basically contemplating the same thing for the NFHS. I believe only 3700 or so did the survey out of the 10,000+ sent out. Of those I am pretty sure 75% were for the change for HS level students. Everyone has the same statement in mind, this will help grow and expand the sport. Nothing has come of it as of yet for the NFHS, but I would expect the conversation to be brought up many more times over the next few years. Nothing wrong with getting a head start on the switch now, because it's bound to happen.
Good article from April 2016 about the survey and the changes.
http://www.flowrestling.org/article/40808-multiple-states-considering-shorts-shirt-uniform-change