Okay, here is another anecdote with an n=2. I used to have an 1982 Honda Civic wagon, similar to the late Klenkemobile. I routinely got 35-40 mpg. I met a woman who had the exact same vehicle except that it had a three speed automatic. She got 23 mpg.
Sure, modern automatic transmissions are more efficient, but they still are not as efficient as a manual in city driving for someone who knows how to optimize efficiency.
No matter how efficient an automatic gets, it will never be able to read your mind. What I mean by that is it can't anticipate what you will do next.
For example, say you are accelerating on the flat and you see a hill up ahead. You decide to leave it in third instead of shifting to fourth. The automatic will shift to fourth and then back to third when the car starts up the hill.