Well THAT is the problem. Reducing class size is not going to make parents more responsible, it's not going to do anything about discipline. That's what people have been saying in this entire thread. Glad you see that now.
You can reduce class size all you want, but you'll still have the discipline problems and lazy parenting that disrupt the educational process.
It isn't that classes have gotten bigger. From the days of the one room schoolhouse when every kid in town was in the same classroom, sizes have been reduced drastically. THAT'S NOT THE DIFFERENCE-MAKER. What has changed is that discipline is lax or non-existent.
Class size can make a difference because we can catch those falling behind before they get frustrated and give up.
But beyond all of that, parental involvement is more influential than any teacher will ever be.