Costco happens to have a couple products I want that I used to bring back by bike until I decided it wasn't worth it unless I was already walking back from the cafe near it.

Swap Costco out with any place I might want to go, and my point doesn't change because whether I can carry a bag of six bagels or eat a pizza in their food court isn't up for debate.

You got one-shot by a triviality. The argument is not whether Costco should be the one building built in more density acoss our cities but whether our cities are hospitable to walking/biking.

Costco just happens to be an example of a business I used to like to bike to near me, but it's adjacent to many other businesses I could have mentioned instead like restaurants, a cafe, and my friend's apartment, not the sole reason the streets exist around it.