Maybe this discrepancy is down to something like Claude code reducing the amount of brain power exhorted. If you have to do 80% less thinking to accomplish a task but the task takes just as long, you may (even rightfully) feel five times more productive even though output didn't change.

And is this a good thing since you can (in theory) multitask and work longer hours, or bad because you're acquiring cognitive debt (see "Your Brain on ChatGPT")?