You are allowed to crush your competitors with economy of scale provided that you don't do it by selling at a loss. That's actually the entire point of economy of scale. The reference in the article is to passing a law against this so clearly what Amazon did is legal now. Furthermore, we don't need a law for this as this type of thing is well handled by a non-compete clause, which I am surprised wasn't in the seller's agreements with Amazon.

FWIW, while I agree this a problem, large box retailers (Whole Foods before the Amazon acquisition, Walmart, etc) are well known for doing this as well.

So if that's the line you draw, it extends further than just tech giants.

If they were the largest retail seller, that would be anti-competitive. Amazon does less than half the revenue of Walmart. Amazon and Costco are the same size.

So I guess all those store brand groceries are anti-competitive behaviors?

Looking at the vast majority of Amazon Basics goods, I just don't see how they would have needed to use marketplace data to come up with what products to sell.

Batteries, clothes (lots of clothes), backpacks, these are all products that are cheap to produce and where brand loyalty plays a large role. People generally trust the name Amazon. It's not rocket science to realize people want cheap clothes and batteries.

Literally every moderately big retailer does this.

Though many of them choose brand that are not as obviously connected with the house. Like half the stuff at Walmart is actually a house brand.