I vehemently disagree with this. There are too many variables and it will only lead to higher product prices. This is not the norm in any industry nor retail business, regardless of what's being sold.
They're not shipping for profit - this is a rarity anywhere. It's called shipping to break even at best. People are getting spoiled by Amazon.
I'm not defending any particular shipping charge on any particular item, but in my experience, based on (multiple of) my orders, it all works out in the end in my favor, and that's before using any monthly coupon.
In my own business, I charge more than postage for shipping and handling. Sometimes much more, and I make no apologies for that. Here are some particulars for my own process.
1. I have to buy shipping supplies - which I have to have shipped to me or go pick up somewhere (sometimes both)
2. It can take a SERIOUS amount of time preparing and packing fragile items
3. For faster deliveries and tracking service I have to use USPS, but I'm in Canada - so I have to process all my shipping online, but then drive my packages 30 minutes away to drop with a private courier who then trucks them to the US.
4. I break even at the postage level on some orders. On some other orders I lose a buck or two not including time or supplies. So when I make money on others, it helps to average everything out. In the end, I'm lucky to break even.