That is also my experience. Doesn't even have to be a 10 year old codebase. Even a 1 year old codebase. Any one that is a serious product that is deployed in production with customers who rely on it.

Not to say that there's no value in AI written code in these codebases, because there is plenty. But this whole thing where 6 agents run overnight and "tada" in the morning with production ready code is...not real.

I don't believe that devs are the audience. They are pushing this to decision makers where they want them to think that the state of the art is further ahead than it is. These folks then think about how helpful it'd be to have 20% of that capability. When there is so much noise in the market, and everyone seems to be overtaking everyone else it, this kind of approach is the only one that gets attention.

Similarly, a lot of the AGI-hype comments exist to expand the scope of the space. It's not real, but it helps to position products and win arguments based on hypotheticals.