These services already have apis that give up the data. So anyone could build data extractors that allow you to regularly pull your Metadata from them and store

These services already have apis that give up the data. So anyone could build data extractors that allow you to regularly pull your Metadata from them and store it in this new datastore. Only the consumers of the data need to change their behavior. If there's easy to use libraries to access the data store and enough demand for it then more and more consumers will adopt it over time.