In reality, the fastest way to empty a plane is the opposite of this. Everybody (who fits) stands in the aisle as soon as the seatbelt light goes off, and they get their stuff down. (If you can't, don't get in the aisle yet.) When the door opens, everybody in the aisle just walks off the plane without stopping. If you're still in a seat, when there's space next to you, step into the aisle, get your stuff down if necessary, and exit without stopping.
This method is almost twice as fast as the standard one. From the viewpoint of the doorway, at any given time there's either a person exiting or a gap. Gaps delay emptying. The idea of waiting for the person who happens to be seated ahead of you to slowly get into the aisle and get their stuff down seems designed to maximize gaps. The method in this post minimizes them.