There are simply so many counterexamples out there of people who have developed projects in a small fraction of the time it would take manually. Whether or not AI is having a positive effect on productivity on average in the industry is a valid question, but it's a statistical one. It's ridiculous to argue that AI has a negative effect on productivity in every single individual case.
We’re seeing no external indicators of large productivity gains. Even assuming that productivity gains in large corporations are swallowed up by inefficiencies, you’d expect externally verifiable metrics to show a 2x or more increase in productivity among indie developers and small companies.