> What's the difference between a messy codebase created by a genAI, and a messy codebase where all the original authors of the code have moved on and aren't available to ask questions?

Very unskilled programmers can use generative AI to create complex code that is hard to understand.

Unskilled programmers on their own write simpler code with more obvious easy to solve mistakes.

On the other hand, all companies I have worked for tried to avoid have unmaintained code (with different levels of success). AI tech debt seems to be added on purpose pushed by upper management.

There is a technical and cultural difference.