Very interesting! I think part of why southwest/unassigned is fastest, is because people are in a hurry to grab the best seat they can since it's an unknown, so they physically move faster.
Not listed in the graphic is front to back, which is what I thought most airlines still do. They seem to be saying all these airlines go back to front including AA, is that the case? I guess IDK because I usually have priority boarding or something but I thought it was still front to back, which is clearly the worst option, because even if people are gathered around the same row/bin in the back-to-front scenario, at least other people can begin their own battles ahead of them. Whereas with front to back, literally 173 people have to wait while a couple of people are putting their stuff in an early row. And I could've sworn that still happens.