The real problem is indeed the code quality, since Copilot does actively provide low-quality codes, and this will bite a lot of people. I guarantee. I don't think this massive learning approach can't be the solution. We need an extra kick.
My shower-thought solution for this garbage-spewing problem is to design a new library with Copilot in mind. Tighten up the interface, and use strict patterns instead of domain-specific hacks.
In other words, we can make libraries so lame that Copilot (and newb programmers) simply can't produce low-quality code. Just disregard smart programmers with fast hands. They don't need any help anyway. Don't even try to target them, because it's gonna cause more stupid flame wars...