The problem with 'organised' boarding is that it makes perfect sense to sensible people but once pax have entered an airport and passed through that curtain of hot air that blows down over the entrance doors their brains remain outside on the pavement where they were blown and they behave thenceforth like a herd of cats.
Pax cannot be organised. They simnply don't co-operate and thereby screw up the system.
I've seen 450 US troops with personal kit board a 747 in six or seven minutes - because they are disciplined and do as they are told.