I suggested a similar idea in the Ace Radio thread last year with what I termed “a radio version of aggregation”. However I only came up with 4 station formats to start with. I like what you’ve suggested to take it further!
I like the idea you have suggested of opt outs when it comes to simulcasting digital/analog content but I suspect regional broadcasters would be too lazy to do this.
Continuing with your 3YB example, if there was say a full time simulcast of 3YB on digital that still provides the current mix of music and talk programming. Listeners on digital would instead have to switch to Coast Rock, Coast Classic, Smooth or Koffee themselves if they wanted music when there was talk programming on the main 3YB.