My guess here is that the reason this engine has not been released yet, is because the procedural part for terrain creation is not done yet ? So right now, its reliant on the fact that you have to download the google maps to get the terrain data. Am I close ?
That's pretty far off
That myth that we are using Google maps to download the terrain comes up quite often, but it would not make sense. Google maps aren't in a suitable format, reconstruction of the data would take eons and not even starting on the legal side. We are only showing a synchronized Google maps window, since the planet is Earth and it's a neat thing to do, but it's not doing anything else than showing the Google maps window synchronized with the in-game camera position.
The engine uses reprocessed terrain elevation data from satellite data sources, and the procedural part adds the detail below the resolution of those data.
In a sense you are right about the procedural part - there's a lot of work to get the engine to render a complete planet with all the biomes, rivers, weather ..
But there's also a lot of work to get the other common functionality that a 3D engine must have - physics, animations, multiple lights ... just try imagining how you'd start coding your game, what would you need for it? I imagine you have already started importing models and setting up physics for vehicles since that's already available in Anteworld - even though that's going to be a game and not an engine, but has some of the engine tools.