Earlier quoted context omitted.
In 1438 there was no supermarkets with huge parking lots that will lure away all your customers. It's not just that people will have to walk to you (so competition located closer will win), they will also have to carry the stuff they buy back to the car, so they'll probably not be willing to buy a lot, or anything heavier. If you're selling souvenirs or t-shirts it's not a big deal, but for people selling say wines o…
People in European city centers shop differently. They more likely don’t even have cars, the stores are smaller, they shop daily or bi-daily rather than weekly like suburbanites do. They aren’t carrying a few bottles of wine and olive oil, they have one bag, and everything is pretty fresh. You can have the same lifestyle almost in the states, just live in a downtown area. Watch out for all the cars though, and wading…
Note that there are exceptions where there are stores. However before you point them out, remember that in a generalization there is specifics that are wrong. Even if there are stores, are there enough stores to cover each tiny neighborhood or do a lucky few get stores and the rest have to drive because the stores are not close enough to be useful.