The apartment buildings are what add density. People who live in single family homes will invariably take the extra 15 to 20 minutes to drive to Costco and save money.
(1) I know this shocks most people used to cookie cutter American suburbs and cities, but you can put an apartment building in a small satellite business district surrounded by single family homes.
(2) Sure. We drive to costco as well. We also shop our local downtown. For example, every Sunday, the local bakery sells off their wares (very nice breads, pies, and cakes) for pennies on the dollar. We also often end up at our local grocery store for sundry items we've run out of or forgotten. Why is preventing people from ever going to costco any concern? I would never suggest to never drive... that's just silly moral policing. I just suggest walking most places because it's way nicer and less stressful.
Here's an example. I bike to my gym every morning. It takes 10 minutes. It'd actually take longer to drive given the stop lights. However, if I lived in the burb I was born in, I'd have to drive, because the nearest gym would be miles away. Or, I'd have to purchase my own gym equipment. Instead, in my city, I have a 24 hour gym within biking distance, and I only need to take neighborhood streets to get there. It's lovely.
There are many services people need regularly that aren't bulk grocery shopping and we don't need to drive to, things like gyms, haircuts, restaurants, specialty hardware, small groceries, etc.
