There is no way to really fix those problems by changing the school system. You can have bandaids, like providing free food at school, but that’s fixing the problem at the wrong level.
I think every school should have the possibility to put your kid in an all-day school, I can't imagine the strain on single parents or parents where both have to work a lot otherwise.
Of course it's not possible to eliminate parents as an important factor of the success of your kid, but you can help.
As I understood it (not a parent and it was not available when I was at school): You have all-day classes and "normal" classes at school. The kids in all-day classes stay together during the day and the kids in the other class go home, it is not an optional add-on. My niece is attending all-day school with a musical focus and likes it very much. All day classes differ between schools and classes, with school on 3-5 afternoons until 4 pm. Supervision is given for homework and studying for exams.
There is a difference between "parents always matter to a child's education" and "let's stop trying to improve schools cause what's the point". The latter is basically the same as "schools are pointless, why have them in the first place?". If you believe that, look at some countries that don't have schools...