I think cars are largely to blame for the sorry state of small businesses. Before moving from America to Tokyo, I had never lived in a place with anything even remotely resembling a walkable city center where you can easily browse and pick up what you need from local businesses. Everything is separated by a 15min+ drive, and I likely need to get on the highway to get there. Atlanta was the worst for this.
In Tokyo I have at least 3 daily grocery stores within a 10 minute walk, plus dozens of other small shops selling all kinds of things I might need. For specialty ingredients I've made an effort to hunt for specialty shops importing Indian, Thai, and Chinese ingredients. My favorite place to go is probably Kappabashi, a street lined with dozens of restaurant supply stores.
I've learned which places I should go for which items, and I love the variety it adds to my routine.