It can, not easily but most of the management needed by said corner store can be automated using SaaS. This approach combined with the app AND the point-of-sales data you can provide to smaller stores by doing so offer benefits for everyone. And the overhead won't be that big for the SaaS start-up as soon as economies of scale kick in IMO.
...unless SaaS providers of this kind of service exists, and the fixed overhead costs bourne by a lot of small shops together.