What continually amazes me about Amazon is that how they repeatedly make themselves appear inept at the operation of that shopping cart.
Only this week SWMBO required seven pens which were ordered as one item in the cart, qty = 7. Amazingly seven separate emails were sent over the space of about an hour reflecting that each pen was separately packed, posted and delivered.
I can't imagine any business I've worked with getting away with that and the many other logistical faux pas I've seen from Amazon without being bankrupted. It seems quite likely that when they say they don't make a profit it's no more than the simple truth.