Their parking lots are also also the standard for customer friendly design with the buffer spacing that sacrifices car density.

Tl;dr: I wouldn't choose Costco to make your argument, LOL.

But on the other hand, every supermarket had 1000 car parking lots to use that space with. Even smaller stores will have ~100. One thing I definitely don't miss compared to downtown city planning that nickle and dimed me everytime I wanted to stop.

A lot of the owners of the smaller markets actually shop at Costco. And you don’t need a car to shop there, you can bike and there are people with vans outside who will take your bike and groceries back home. Costco also offers local delivery.

I wouldn’t say it diminishes from the urban design you mention, in many ways it facilitates it.

This doesn’t work. Small businesses have a price floor set by their tiny scale and lack of leverage with suppliers.

You should be hoping that Costco stays in business and large every day grocery stores (Kroger, Target Grocery, etc.) don't last.

I'm fortunate enough to be able to travel by PEV/Bike to one but there's another Costco near me which is assailed on all sides by freeways and would be impossible to reach by anything other than car.