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 know he acknowledges the capitalistic barrier to this solution but the other issue I see most often are folks simply not being there by boarding time. These methods all assume you would have everyone ready to board in their respective groups at once. I would imagine that throwing a few folks out of order in even the modified Steffen approach could bring down the theoretical time by quote a bit.
I think the reason people aren't there at their zone's boarding time is because they only print the initial boarding time on the ticket and just wing it after that.