>1. AI doesn't improve productivity and people just have cognitive biases. (logical, but I also don't think it's true from what I know...)

It is from what Ive seen. It has the same visible effect on devs as a slot machine giving out coins when it spits out something correct. Their faces light up with delight when it finally nails something.

This would explain the study that showed a 20% decline in actual productivity where people "felt" 20% more productive.