It seems like a pop can only move to an empty slot on another planet, which would make migration between planets with no empty slots impossible. In the case of two planets being inhabited with one species each, and which both dislike the type of planet they live on but like the planet the others live on, they still wouldn't be able to migrate.



Is there any mechanic around this build-up? Doesn't it otherwise make migration almost irrelevant late game, when all planets are full?