In the years I taught grades 4-12, I saw many students succeed and I saw some fail. It should be no great surprise that many of those who succeeded were the students whose families valued education and insisted that their kids take ownership of their future. By that, I mean, that they encouraged them to be as independent as possible, to take pride in their learning and accomplishments and to take personal responsibility for their own success.
When I taught elementary school, these experiences were not unusual: parents driving their kids to school, even though they lived two blocks away, parents unpacking backpacks, setting up their child's desk and even cleaning it out, parents bringing their child a McDonald's lunch and parents rushing back home to get a forgotten book, pen or other school supply. These helicopter parents were doing their kids no favors. They were promoting their child's further dependence on them to solve all their problems. A child tends to value something more when they take personal responsibility for it. When they solve their own problems, it's a good thing. Again, no big news to any parent.
If a child forgets a pen, homework assignment, book, etc. so what? There may be temporary consequences, but the world will not end and their grade will not significantly change by one or two lapses. If it becomes a habit, then that's something the child and parent have to work on together to help find a way to overcome their forgetfulness. But Mom or Dad doing everything for them or turning in homework for them makes as much sense as doing their SAT's for them. This is the child's education. Make them realize that they have control of it and a stake in their own future.
Students who have figured out how to get the most out of their education are the ones who become proactive, not reactive. They anticipate needs and deadlines and difficulties and try to work them out ahead of time. They succeed because they take an interest and they know their success depends on what THEY do and not what their parents or anyone else does.
Some kids definitely need follow-ups or a push to help their motivation. I'm not suggesting that all kids can just miraculously take control and become great students. That's not going to happen. It's perfectly okay to check the teacher's homework line or website or whatever methods she or he communicates with the home. It's good to be in the know. It also lets your child or children know that you are interested. But you can do spot checks once or twice a week. You don't have to do it every day. If the child misses an assignment or gets a bad grade, they WILL learn from that and hopefully not repeat their mistakes.
Just for the record, schools are NOT all about positive learning. Sometimes the mistakes we make or that students make teach more than successes. It all helps in shaping our habits, values and personality. But the sooner we all realize that our success or failures depend more upon us than others, the more satisfying the rewards reaped later.