I find that Costco in store generally has stuff that tends to follow local consumer preferences.

It is worth mentioning that Costco.com does not stock the same things that the physical stores sell, more-so than any other retailer I know of. And different stores have a lot of latitude in what they stock.

My nearest store has tons of things like sugar free sodas, pro-biotic soda, kombucha, no sugar added juices, and juice shots, etc... It might just be the local Costco catering to their market.