When you weigh 200 lbs., you don't want all that weight on a 3-inch wide strip of foot-- it's like running in high heels.

Well, aren't most marathon runners, etc., stringy, lean, gaunt creatures that don't get up to 200 lbs? (Just a thought)

And I agree with your point #5--it doesn't matter how engineered, high-tech or expensive a shoe you buy if it doesn't fit your foot. (I have wide feet with a high arch, so ninety percent of the shoes out there don't fit me too well.)