[LanceH]

Costco buys products and resells them. Costco's research numbers are paid for entirely by Costco.

Amazon rents space to merchants where those items are sold through the site for a fee. Amazon is never on the hook for a sale and is basically getting paid to do the market research to set up as a competitor.

Yes, Costco does do some referral sales but I can't think of anything which has gone on to be a Kirkland product.