By "platform co-op," the OP means an organization as proposed and promoted by https://platform.coop/ : "Platform cooperatives are businesses that use a website, mobile app, or protocol to sell goods or services. They rely on democratic decision-making and shared ownership of the platform by workers and users." Sounds great... but it's unclear to me if the people promoting these organizations have fully thought through the kinds of incentives necessary for scaling up successfully in order to compete with the likes of Uber.