Also food delivery.

In Finland, there used to be "pizza-online" which was really just a directory and ordering system for restaurants that already did delivery themselves.

They took a very small comission, as the site didn't really do anything except connect restaurant and customer (and provide a review platform). For a long time, they didn't even have an app.

You'd log in, select a restaurant, browse their menu and place an order. The order goes to the restaurant, and after that the site's job was done.

It was massively succesful. Every hole in-the-wall pizza place was on there. Finding good food was easy and cheap, and the restaurants reached more customers than ever. And the platform including reviews led to competition in not just price, but quality.

Then pizza-online sold to foodora, and they got shut down, and participating restaurant were no longer allowed to deliver themselves, and the cut taken by the platform skyrocketed.

Flohmarkt is probably the closest. Basically federated ebay.

https://codeberg.org/flohmarkt/flohmarkt

I think what you want is a CO OP. It would be nice if the software was FOSS of course.

But a coop would make things like uber type services be worker owned.

Also members can make decisoons.

The software for that is relatively easy

Getting people to use it will be next to impossible. Without a strong marketing budget, it would take decades at beat before even a small percentage of people would be using it (see Linux desktop) as its all word of mouth and initially only the nerds in the know would be using it for years

I would like to see such a thing. But I would add API for accessing it with a dedicated app. Allows for better performance and features like filtering across multiple shops at once an even allows integration in scripts.