Competing in any market isn’t easy, especially with low margins. If it was, someone would be doing it, since people have a goal to earn money.

The comment I replied claimed Amazon didn’t have competition, to which I wanted to point out that the retail side of Amazon has a ton of competition. And single digit profit margins are pretty hard proof of competition, and/or low barrier to entry. Because again, people have a goal of earning money, and the only reason they would accept single digit margins is if others would take their business.