Evolving Information Symmetry in Baseball

Twenty years ago, no fans had access to, for example, the data about pitch type and speed that is now relatively easily available, even decent video of major or minor league players was hard to come by. Thirty years ago up to date data of minor league games was unavailable for most fans. This made is possible for insiders to either know more than most fans, or by alluding to hard to get information, pretend they had more information than most fans.