Aristotle on why the education of the young should be common

A continuation of this post.

Aristotle explains why education of citizens must be common:

Since the whole city has one end, it is manifest that everyone must also have one and the same education and that taking care of this education must be a common matter. It must not be private in the way it is now, when everyone takes care of their own children privately and teaches them whatever private learning they think best. Of common things, the training too must be common.

At the same time, no citizen should even think that he belongs to himself but instead that each belongs to the city, for each is part of the city. The care of each part, however, naturally looks to the care of the whole, and to this extent praise might be due to the Spartans, for they devote the most serious attention to their children and do so in common. (Politics, 8.1 1337a21-32; trans. Peter Simpson.)

At the same time, Aristotle acknowledges that most cities neglect legislation regarding the education of the young, and do not have any sort of common regimen:

In most cities these matters are neglected , and each lives as he wishes, giving sacred law, in Cyclops' fashion, to his wife and children. So while it would be best if the care became a common one and were correctly managed and if doing this were a possibility, yet, in the absence of common care, it would seem proper for each individually to promtoe the virtue of his children and friends, or at least to make that his choice. But from what has been said, it would seem that one would be better able to do this if one became a legislator. For while common cares clearly become common through the laws, they become decent through serious laws. (NE 10.9, 1180a25-34; trans. Peter Simpson.)

And so the virtuous are left to themselves, and must become legislators within the household, setting down laws for the training of their children.

What if there is a common education, but it is not rightly ordered? Perhaps it is in accordance with the constitution of the polity, but the constitution is not a good one, or produces bad people? One should avoid that education as much as one can, and if that is not possible, consider separating and entering a different community. What choice does one have, if one is concerned with virtue and raising one's children in virtue?