@thor i think the lazyness is a big reason for this. it's easier to click something on amazon instead of typing in your address on yet another shop.
i can't remember when/if i got sold shit by a small shop. the occasional mishap, but all of them were handled properly. last time was when i've got the wrong toothbrushes, got my money back quick _and_ could keep the wrong ones. that doesn't happen with bezos.