Very little as it turns out.
Not food-you can shop for food online without sending “away”. In the late 80’s I worked for San Francisco Grocery Express. The customer could place an order and get a delivery window 4 hours later. Place your order @ 1:30 and get delivery between 6–8. We delivered all groceries, we had a connection w/nearby butcher, delivered flowers (grocery store quality) and each week we featured a local restaurant and delivered selected meals from them. For the holidays we delivered full dinners , this was before the supermarkets did. This concept was way before it’s time because most people didn’t have home computers, but today I shop online through the local supermarket. In the future I can see grocery distribution centers with regular routes like UPS.
As far as clothing goes we already have places like QVC which sells different kinds of clothing but are very standard in their sizing. Between Land’s End, Hanes, and QVC, I haven’t shopped for clothing in a brick and morter store for 5 years. One time I found myself in a rehab hospital far from home without enough appropriate clothing. I got on line and 48 hours later I had 3 outfits I could wear for physical therapy.
Just like Walmart can demand certain specifications for their products because of their buying power, there is no reason a clothing distributor couldn’t.
Most big ticket items could be purchased on line or have a small area showroom.
The same could be said of tailored clothing and wedding dresses. The measurements could be taken and a limited # of styles available in a display room. It is pretty much like that now except there are crazy numbers of choices. Think about inputting the bride’s honest dimensions and you can try out every stle of dress w/online model.
I can’t think of anything I wouldn’t buy on line.
There is almost anything from Amazon and most big dept stores do online sales.