nother implicit assumption here is that we're all born equal.

If your relative wealth is a result of genetics, not effort, do you still have an absolute moral claim on it?

Aren't societies semi-stable, self-reinforcing, whatever their current wellbeing is?

Well, I'm not an illtetrate farm labourer like my ancestors.

Assuming it was redistribution that made you wealthy and educated, does it work reliably on the majority of poor people?

Why would it have to? You can argue that people have a right to the opportunity of an education, irrespective of outcomes, and you can argue that educating people up to their potential has a nett positive effect. Neither argument requires education to lead to positive outcomes in every individual case.

This argument only makes sense if you already believe that redistribution reliably works,

Western societies introduced universal free education over a century ago, and are now much richer.