"ou buy your stuff, in bulk if you one, pay $10 (1000-something yen IIRC), and voila they'll deliver it to your apartment. Every major train/subway station/nexus has a mall so shopping (and buying delivery) is also conveniently located.) Try to do that anywhere in the US."
You may know alot about Japan but your ignorance of the USA is showing here. What you describe is possible in many parts of the USA.
Our family hardly ever shops anymore, we just buy it all online and have it delivered. Groceries too. The only place we ever go out to is farmer's markets, because a) they don't deliver, and b) they're often more of an experience than just a shopping trip.
You are showing your ignorance here. Of course Japan also have online stores, but that's another thing entirely.
What the GP said was to be able to *physically* go to a store, *hand pick* what you want to pick (i.e. you can pick and choose, e.g., the fruits, one by one), and the pay at the counter THEN have the store deliver what you picked to your home.
Living in the US you might think that is stupid, why would you take the trouble to go (drive) to the mall and then not carry the stuff back home? The difference is, in Japan (and also applies to many Asian metropolis), as the GP mentioned, there are malls *everywhere*. Next to metro stations, around the corner, right beneath your home, etc.
So during the normal course of a work day, you would probably pass malls/shops on your way to work, during lunch break, and on your way home. Then it became natural for you to scan the shops and probably, once in a while, notice something you want to buy, but you are on your way to work/lunch break/dine with friends/etc and obviously *not driving*, so you don't want to carry the stuff with you around. THAT's where the delivery comes in to play. You pick, you pay, and they deliver while you go on your merry way, just 3 minutes spent.
That convenience of practically going through shopping malls along the way of everywhere you go is what GP meant. You are literally 10 minutes away from everything you need/want to buy, almost all the time, and you never need to "take time" to buy anything at all.
And no, Americans living in suburbs where they have to drive 10 minutes to buy toilet paper, and do a "shopping trip" to Walmart once a week just to stock up on groceries won't be able to imagine what it is like, the convenience of being able to buy a fresh apple (just one), on the way home, every day, by just stopping for 30 seconds at the grocery that you pass by daily anyway.