I also think that AI written code- is just not read. People hate code-reviews, and actively refuse to read code- because that is hard work, reading into other peoples thoughts and ideas.
This is why pushing for new code, rewrites, new frameworks is so popular. https://www.joelonsoftware.com/2000/04/06/things-you-should-...
So a ton of ai-generated code- is just that, never read. Its generated, tested against test-functions - and thats it. I wouldn't wonder, if some of these devs themselves have only marginal ideas whats in there codebases and why.
I have mostly worked in aerospace software, and find this rather horrifying. I suppose, if your tests are in fact good and comprehensive enough, there could be a logical argument for not needing to understand the code, but if we're talking people's safety in the hands of your software, I don't know if there is any number of tests I would accept in exchange for willingly giving up understanding of the code.
You're transferring the need to be really good at coding and understanding code to the need to be really good at testing and understanding tests, which 9/10 times requires being good at coding and understanding code. There are no free lunches.