"trying on shoes in a shoe shop"
If all your shoes are the same type of sneakers you buy over and over probably you don't need to. Or if you buy only hand-made shoes from shops where the shoemakers have a 3D-printed model of your feet from a high-res laser scan.
Don't know onepoll which kind of shoe-buyers interviewed - if they were software developers or their Sillycon Valley CEOs.
Otherwise it's a basic safety precaution to avoid to curse the day you bought them every time you have to wear them and suffer the pain of hell.