I own a consumer goods business and sell via Amazon and traditional retailers. Amazon's 30% to 40% fee is much less than traditional retail, which starts at 50%. Amazon is where I get my best margins.
It's great that we can use this as reference for what it used to be. Presumably, this is what competition should bring in: "traditional retail sucked, so amazon comes in and takes over it by offering something better."
The same thing would still apply now too: "if sellers are able to offer their goods elsewhere for cheaper, they should be able to", instead of being forced to raise prices everywhere.
It fits with my understanding of traditional retail as pretty brutal for new entrants, taking more of a cut and putting up a much higher barrier to entry than Amazon.
Ebay may have lower fees, but Amazon is where many people go for convenience.
The same thing would still apply now too: "if sellers are able to offer their goods elsewhere for cheaper, they should be able to", instead of being forced to raise prices everywhere.