The Blue Network, being the smaller of the pair, positioned itself as somewhat more hi-brow than its big sister. For example Milton Cross' iconic broadcasts of the Metropolitan Opera were staples on the Blue Network whereas the Grand Ole Opry was carried from the late 1930's into the mid-1950's on the Red Network.
The situation then is somewhat analogous to the current ESPN and its various subnets, each of which tries to achieve some distinct branding while under the aegis of the mothership.
That’s interesting, and we didn’t know that history, either.
I don’t recall Mr. Walker ever mentioning anything about the Red and Blue networks, but I’ll bet he knows all about them.
As Vision said, you can e-mail Mr. Walker, and he would likely respond. He’s good about answering enquiring e-mails.
He seems to just play what he (and the audience) likes, though, not necessarily to balance Red and Blue programming.