I share your concern, but perhaps for a different reason. I think the more code is added, the more problems/bugs emerge, whether a human or AI codes it.

However, with AI coding tools it's becoming a lot easier to write A LOT of code. And all this code (similar to when a human would write it) adds complexity and bugs. So it's not just the quality, it's also the quantity of code that damages existing code bases (in my view).