The playbook thing isn't a big deal. A playbook is the thing that you give your guys during week 1 install at the start of spring or fall camp, and contains the plays that are your bread and butter. Here's Mike Leach's playbook from 1999:
https://jameslightfootball.files.wordpress.com/2015/03/1999-oklahoma-air-raid-mike-leach.pdf4-verticals, one of our most common plays, is on the seventh page of that document. That's how much information is in a playbook for any given play. At this point defenses have 26 games of all-22 footage of Tony's offense at Cal, from both pressbox and end zone angles. A D1 coordinator could come up with that playbook after a day of film study (actually, that and a lot more is exactly what GA's do two weeks before playing an opponent).
The question is, how do you get from there to a gameplan that can confuse opposing defenses? The players learn the playbook first, so that they know the basics of the route that they're running on any given play, but then there are hours and hours of film study and practice where the coaches and players watch the play against different coverages and techniques, talking about the finer points of getting open against whatever defense they're facing. In film study the coaches don't just say "read that guy," they give their players all of the specifics that they need to run the offense at maximum efficiency. None of that's in the playbook, and that's the first place where coaches who use the exact same plays start to differ from each other.
Then, once that's coached up, you get into the gameplan specific coaching points each week. "They like to run coverage X, so we're going to start attacking them with play Y so that we can open up play Z," or "that safety gets caught looking into the backfield, so when we run this concept change up the order of your read." That's the really important information, and it's obviously not in the playbook either.
Then finally, there are gameplan specific tagged variants of your base plays, or new/trick plays added on a game-by-game basis. These are the kinds of things that might never have been on tape, and they aren't in your base playbook, either.
If a GA did get into the conference call, so that they could actually hear Tony talk about how he approaches gameplanning, what new ideas he's considering, and how he thinks about strategy, that would be more of a problem, because they would be in a better position to anticipate what'll be on his mind during gameplanning, and to predict changes from previous years' strategies, but the playbook isn't that valuable. Nick Saban's LSU and Alabama playbooks have been online for years, and they have way, way more information about his defense than Air Raid playbooks have about our offense.
