On the same line of thinking, how many of those passengers took a little longer doing something—getting out of their seats, moving through the cabins, sliding down the ramps or otherwise exiting the planes, or even evacuating the area afterwards because they were texting, talking, or videoing something on their phones?
The best way to fundamentally change this is by means of drills - like fire drills, cruise ship “muster” drills and the like. No individual airline could ever do this because they don’t have the time and also it would send the wrong message.
What *could* be done would be a mandatory “flyers ed” course (by analogy) with drivers ed - where you practice evac procedures on a mock up plane in order to be permitted to fly. Which sounds like incredibly “nanny state” but from a purely practical standpoint *could* save a life or two over time.