I think the only way it can possibly work is if procedural generation really gets figured out. Designing an island is already an entire multi year game dev cycle, scaling up the number of people needed to design a continent, or a planet, or multiple planets, just isn't feasible. Devs get away with it for now by just having lower fidelity for larger spaces, but the bigger you go the more you need to fudge and the more obvious your algorithm gets.

We can simulate a big bang, planetary orbits, civilizations rising and interacting with each other - but we can't tell a computer to design all of the 3D models of buildings that you would need to populate a procedurally generated city. Yet.