The seats are assigned. People have been standing in line for 15 minutes now. Why on earth would anyone want to stand there, when they could just sit and wait until the line clears?
I understand wanting to get off a plane ASAP, but boarding? You just end up sitting on the plane, waiting for everyone else to get on.
I didn’t realize this factor until I started traveling with my wife, who packs much more than me. I’ve always fit everything into a single personal item that goes under the seat, which has always meant casually reading a book until my zone is nearly finished boarding