I took a marketing geography class in university. The lesson was keep a good distance from your competition and you will be a-okay.
I do see cases of that in Toronto, as we have the College Street computer store cluster, or Queen Street for fashion goods.
Clustering does save a bunch of time when you are shopping for a specific item. However it can become a pain in the butt when you have to travel to the “Computer Center” to get an iPhone charger.