If i understand you correctly, one does have to pick a big industry, pick a niche, (sell in bulk,) combine it with something else to add more value compared to similar products?
The specifics relate to the market and the kinds of product sold. You are not going to make money shipping individual 50lb bags of dog food to people, but you might be able to make money shipping pallets of dog food to people. Things like building communities or creating content are really just another form of advertizing that is theoretically cheaper to create in the long run than Adwords.