What truly set them apart wasn't inventory. Any large physical retailer could match back them.

It was inventory plus ease of use. Which is customer obsession.

One click purchase. Next day delivery. Flat fee shipping (prime). No questions asked drop-off returns. True, useful reviews. Good algorithmic sorting. Best in class logistics.

It was really much better than anything else online.

Now reviews are shit, searching products is a nightmare of sorting through clones and knockoffs, marketplace returns are hit or miss... and that's why it's worse.