Non real-time as in generating levels for your game to release it's doable today. Real-time it will probably be doable soon, especially for shared-world games w

Non real-time as in generating levels for your game to release it's doable today. Real-time it will probably be doable soon, especially for shared-world games where a server can generate for multiple people at a time rather than single-player. Even real-time today it should be doable if you create your game with that in mind. You really don't need to generate all the textures, just a compact representation of the level which is to be rendered normally after the fact.