That is not what they said. They touched on the basic problem when they quoted Day. If you don't execute (get first downs) then going "faster" just hands the ball back to the opponent faster.
The problem was execution, not speed. We just saw two games in a row where the young QB was visibly sped up, confused and making mistakes because of what better defenses were doing to him. Unfortunately, speeding up a guy who's not able to execute already just isn't going to work.
The problem wasn't the speed, it was the young QB's development (along with the OL issues).
Going forward, if you have a skill advantage the best strategy is efficiency. In some tactical situations you can absolutely apply tempo but as a high level approach, efficiency is the best path if you are the more skilled team.