I find that it depends a lot on the project.

I'm doing solo mobile app projects, and I have no need to iterate on specs. The bottleneck is QA testing whether it works on the phone.

I don't need to carefully review and understand the implementation. It's not important whether I understand the details of how exactly UICollectionView in Apple's UIKit works.

I see that my implementation works on different physical devices, my tests cover device rotation, and I checked the memory allocations in the Instruments tool.

It has been some months of part-time work on my side, and I will publish this iOS app soon.

Without AI I could not have done it, the scope of the features is too large. The project is around 100k LOC.

It is not true that projects become unmaintainable and abandoned because of agentic engineering, or even vibecoding if you want to call it that.