I'm really curious as to why these type of engines aren't being fully fleshed out into games yet. With procedurally generated terrains, we could visit different planets and entire worlds like what Outerra can do, yet it's been years and years and still no one has come out with anything. Some serious issues are going on or something, but this really is the future of gaming. Can't wait for an Xwing universe type game where you can visit other planets, hop out of your aircraft, fight #%&*$# and then jump back in and go somewhere else. One can dream.

...because what you need are also procedurally generated cities. Landscapes, as complex as they are, are the easy part. Procedurally generated visible signs of technological civilizations, that's a whole other issue, especially since everybody knows from his daily life how a city should look like. The required level of detail is mind blowing.

As far as I know Outerra is being developed by just a small team of programmers. I don't think creating procedurally generated worlds is the problem because It's already been done in the past and right now we have Space Engine and other project in the works. Also Outerra uses real elevation data.

I think the problem is most of the people are looking for a more accessible entertainment. Even if a simulator-game was created using the Outerra engine despite the incredible graphics, it's a niche that not all gamers find it attractive.

That's why games like Modern warfare sells millions and then a game/sim like Orbiter or Space Engine is barely known.