I feel like this becomes kind of unacceptable as soon as you take on your first developer employee. 10K LOC changes from the CTO is fine when it's only the CTO working on the project.

Hell, for my hobby projects, I try to keep individual commits under 50-100 lines of code.

Templates and templating languages are still a thing. Source generators are a thing. Languages that support macros exist. Metaprogramming is always an option. Systems that write systems…

If these AIs are so smart, why the giant LOCs?

Sure, it’s cheaper today than yesterday to write out boilerplate, but programming is about eliminating boilerplate and using more powerful abstractions. It’s easy to save time doing lots of repetitive nonsense, stopping the nonsense should be the point.