If, as an adult, you missed work as frequently as some of the poorly raised children, you would be fired. Yet you expect teachers to be successful when the kids don't show up.
I'll make this bet. Of the non-truants, most are probably above average students, if not in the top ten. See, their parents care. Their parents get it. Their parents realize a good education is imperative to a successful life.
However to the Miller High Life, sit on a bar stool and don't ever work parent, their kids don't have a chance.