I worked at a startup that made exactly that, but the product failed and the company pivoted to other ways to support local businesses. Most local businesses didn't want to put much effort into getting their products listed online.
I think that’s the hard problem to solve and where a startup might succeed. Anyone can throw together an e-commerce site, but if the item creation is harder than making an insta post then small local shops won’t use it. It would be really hard though, because multichannel purchase and stock tracking and POS integration are all really difficult and all three would be a nightmare.
