Open Street Map is a nice analogy for what could work. Aside from the open source maintenance of the map, there's also tons of corporate help in the background. Companies that are delivering OSM as a service or relying on it for their own services have an interest in making it better. MapBox, for example, apparently pays tons of people a salary who are contributing upstream to Open Street Map. If we can get an Apple/Microsoft/Other players collab maybe a venerable alternative can actually be built.