So true! All of those factors exert an enormous effect on the outcome of a student's education. Unfortunately (except for the school resources issue) they are all completely out of the teacher/school/district's ability to control.
Whenever teacher/school issues come up, it is important to remember that far beyond anything a school or teacher can do, the single-most important factor in a child's education (or their life in general!) is their PARENTS. If a kid has parents who value education, discipline their kids and make time for learning at home, that kid can do just fine no matter what kind of conditions they experience at school. Conversely, it takes a Stand and Deliver-style superteacher to be able to coax success out of a kid growing up in a home where education is not valued and productive personal habits are not modeled.
The biggest problem with education? There are far, far too many parents out there who have absolutely no business raising children at all. We require tests for people to operate a jet ski, but when it comes to absolute power and responsibility for a human child, anybody can do it! That's your right! Don't worry about saddling the rest of society with your child who doesn't stand a snowball's chance in hell of ending up well-adjusted, educated or successful. It's YOUR kid.
I understand that people who are struggling with extreme poverty are often too caught up with bare survival to find the time to focus on their children's educational needs. That is really awful and sad. It is especially sad for their children.
The fact is, as long as society is full of self-centered, thoughtless parents who either fail to understand the basic components of child-rearing or are too busy surviving to care, we will be plagued with students who are going to struggle no matter how great of an educational system they are placed in.
That being said, perhaps the only way to raise a generation of education-valuing, quality parents is to do what we can to create them. So maybe it is best after all to focus on what CAN be done - effective teaching methods for today's teachers. Hopefully a much-improved school system can help raise the prospects of children whose parents are doing nothing to give them a hand up. And then they in turn can become the kinds of nurturing, education-valuing parents that their own children deserve.