This doesn't really make sense to me. On the internet hyper-specialisation is obvious since space is virtually unlimited. But in real life, I mean, real estate is limited so why wouldn't darwinian market forces make a shop with product diversity + epsilon out compete a shop with a more niche spectrum of products, until only walmart and such remains?
Many reasons. First, WalMart doesn't have everything. Only a few people in any city are interested in buying specialty items, it doesn't make sense to WalMart to stock that everywhere when some stores will never have a sale. A specialty store brings in customers from all over the city. A human who knows one product well is very useful. WalMart salesmen don't know their product. Going to a specialist who knows the pro…
I think you also need a sanely designed city with effective public transport. For example, Atlanta or Charlotte have millions of people, including hobbyists and artists and enthusiasts, but I don't think many of the shops in the linked article would survive in a strip mall.