All of these boarding methods assume that
: all of the people will be at the gate to board at the same time
: people will know what 'number' in the queue they are to board
: people listen to announcements

Theory is great in theory land, unfortunately we live (or most of us do) in the real world where
: people don't read signs/boarding cards
: people don't listen
: people don't give a sh!t

Boarding processes are only as good as the people doing the boarding and the people being boarded!!