[defatigable]

That's not my experience. I agree that a project of any real size takes quite a bit longer than a week. But it's composed of lots of, well, week or two long subprojects. And if the AI coding tool is condensing week long projects into a day, that's a huge benefit.

Concretely speaking (well as concretely as I feel like being without piercing pseudonymity), at my last job I worked on a multi year rewrite of one of our core services. Within that rewrite were ton of much smaller projects that were a few weeks to a month long - refactor this algorithm, improve the load balancing, add a new sharding strategy, etc. An AI tool would definitely not have sped up the whole process. It's not going to, say, speed up figuring out and handling intra-team dependencies or figuring out product design. But speeding up those smaller coding subprojects would have been a huge benefit.

I'm not making any strong claims in my post. I don't have the experience of AI projects allowing me to one shot large projects. But OP asked if anyone has concrete experience with AI coding tools speeding up development, and the answer is yes, I do.