Phil's philosophy (and Norm's before him) is to force offenses to move the ball in small increments, relying on offenses to eventually make mistakes. That approach has been very effective over the years against average teams, but, it backfires against top-tier teams.
What I would like to see him do is practice a "plan B" to have ready against the better offenses. For it to be effective, you would have to devote regular practice time so that the players can change things up quickly without having to overthink, and that may be the problem. Phil believes in hammering the details of his scheme every week. Not doing so is risky in his mind, but the reality is the better offenses are not going to beat themselves.
I don't think he necessarily has to blitz a lot more, but have calls where players jump to the line just before the snap with the option of bailing out at the last second. At the very least, making the opposing players and coaches confused and uncomfortable during the flow of the game can't hurt.