Malone's judgment was correct. When the offense and defense switched, JR switched to defending Irving, and the Celtics abandoned the 15 pick and roll.
Of course, they also didn't run the 12 pick and roll. Stevens' strategy was to exhaust both Hansen and Jokic, but if you know that it's JR defending Irving, and Irving still insists on running the 12 pick and roll to match up against Hansen, that's not strategic exhaustion, but purely asking for trouble.
Hansen was liberated on the defensive end, allowing him to fully exert himself offensively.
Moreover, in this quarter, the Cavaliers needed Hansen to continuously play isolation offense.
Even though the Celtics abandoned the 15 pick and roll, they did not give up on wearing down Jokic.
And they have the capability to do so.
Irving and Durant may not be stars who excel at both offense and defense, but their isolation ability is maxed out.