Bodegas have a business model where all manner of shady practices are commonplace, that a corporate, well capitalized, operator would not be able to use. There are, of course, offsetting scale disadvantages.
There’s also the willingness of the owner and family to work hours and accept physical risks that no (documented) employee would accept. And willingness to buy soda and snacks from some random with a box truck that isn’t a representative of Coke/Pepsi, Frito Lay or Mondelez.
There are lots of reasons why bodegas operate in places where a 7-11, Quiktrip or Circle-K wouldn’t. These well organized chains have too much of a paper trail and deep pockets to go after.
Never mind grocery store chains which in the US are predicated on a 40,000 square foot box minimum with loading bays a semi truck can back up to.