[zdragnar]

Zoning and sanitary regulations, presumably.

For zoning, there's plenty of places that don't allow commercial operations near residential zones- hence the push for more mixed-use zoning. Unfortunately, urban environments still have very high rents, so to stay cheap enough you'd have to get permission to operate a good truck or sidewalk stand.

For regulations, there's no way to run (or rent) a commercial kitchen and sell low cost freshly made food and make enough money, especially if you aren't operating out of a food truck. There's several other licenses involved depending on the nature of the business.