I think we need to disentangle the individual problems here. One problem is the compulsive "child must go to the Gymnasium," which would be easy to solve if the three-tier school system were used as such. Genuine overburdening in primary school can be managed through special schools, if one is willing to do so. Another problem is language, as language is the fundamental prerequisite for all subjects. This can be compensated for to some extent through appropriate preschool or childcare. However, this also requires that children actually attend these and that there are enough places available. And then there is the issue of parental behavior. Sure, you can offer afternoon care and homework help. But whether a child is pacified in front of the TV or regularly read to makes a huge difference. This also correlates with social background, but the school can only compensate for it to a limited extent.