Youll find this is a worldwide problem not confined to just one country and one carrier. There are many reasons why pax are late and a lot has to do with cultural excuses so Ive found:
islamic States: 'sorry just had to get in my mid-afternoon prayers'
Aussies: 'Hey youve just got enough got time for another roadey mate!'
S.E. Asians.: 'Patience is a virtue. No need to rush.'
Poms: 'The M4 was packed!'
ad infinitem.
I agree to hell with late pax. If 149 manage to show up on time why give a rats about the late 150th? Unless its delays incurred by a late conecting flight then b*gger them.