neat graphs, and I agree about disregarding cross chained gears. I too pretty much avoid the top couple of gears while in the granny (never use 8th and 9th gear, very rarely 7th)
In the mid ring I tend to not use the bottom one and the top one, although I do use the smallest cog sometimes, but not for extended periods.
In the big ring, I really only use the top half of the cassette
and overall, I like a mid ring that covers the majority of riding, and I've mentioned this before about your gearing, that for me a 42t mid ring is just too big. On my 50/39/26 bike, the 39 is great for unloaded and loaded to a certain extent, but I would very much prefer a 36 or even 34 for loaded touring, for my comfortable cadence and what my legs can put out comfortably, a 42 is too tall.
I very much agree with you in that the priority for closer gearing should be in the speed range that you will be going the majority of the time, this just makes sense.
I bet we ride around the same speed twiddling around town. I'll add: A 32 middle on 26in wheels for all around unloaded riding is too small.
My all around road ride has a 13-28 7 speed free married to a 48-36-24 I use 5,6,3 gears respectively, daily with three others once in a while when I want to avoid a ring shift.