There's a good chance this will produce BETTER code than "eligible" low-grade coders which do this now. You're overly optimistic about them
The currently semi-bad low-grade coders will get pushed out and replaced with even WORSE ones.
The worse ones will be the ones responsible for choosing and approving the code which was generated by AI.
So let's say there is a "Q(c)" which measures worst possible quality of code c.
If the person who monitors this things has a bad worst possible quality Q(c), the code will also have a bad worst possible quality Q(c).
If current code has Q=0.1, "AI" has Q=0.3 and "person who monitors" has Q=0.02 end result might still be better. It's not a simple multiplication of coefficients there. Better baseline would pull result higher