Based on your description, I think your tl;dr was meant to read as, "Banning bags has no measurable benefit."
We banned bags in Austin a few years ago... but now for the most part I just pay $0.25 every time I need a bag. And now I have to buy special purpose dog-shit bags instead of just reusing supermarket bags.
What I do like though is seeing less plastic bags on the side of the road. Helps keep the place from looking like an oil field construction zone.