Well for that matter, I have known people who buy fashion items online (that fit perfectly) use them on a dinner out and then return them because they don't fit or are not the expected colour, etc.
Still, since as you say these online sellers must calculate the prices of these goods to cover these return expenses, the other "normal" clients pay more and BTW there are thousands, millions packets going and returning (it is time, money, traffic, etc.).
It's a little different. For some of the fashion domains I'm thinking of don't have "normal" consumers, and most goods cost about the same as half of my entire wardrobe. For others, shopping is more like entertainment, and it's about the experience.
Still, since as you say these online sellers must calculate the prices of these goods to cover these return expenses, the other "normal" clients pay more and BTW there are thousands, millions packets going and returning (it is time, money, traffic, etc.).