Based on what I've seen and heard, you have the happy path working and that's what the pro-AI people are describing with huge speedups. Figuring out and fixing the edge cases and failure modes is getting pushed into the review stage or even users, so it doesn't count towards the development time. It can even count as more speed if it generates more cases that get handled quickly.

I'm not sure I agree with this approach, or at least it doesn't work in my area. It's like self driving cars. Having 90% reliability is almost as good as 0%. I have to be confident the thing is gonna work, correctly, or at worst fail predictably.

I can see that there's a lot of applications where things can just randomly fail and you retry / restart, that helps with crashes.

But the AI can't make it not crash, what's to say it does the right thing when it succeeds? Again, depends on the relative cost of errors etc.