An academic Great Gatsby Curve – How much academic success is inherited?

It's the Mathew principle all the way down.

Actually it's a bit worse, in the sense that if you exhibit competence without the "appropriate pedigree" all you'll get is punishment.

Yep, this. Another reason why the left has lost all public trust in institutions. Too much of elitism and connections.

This is completely general and independent of left/right liberal/conservative dualities.