Once you have enough upgrades to make it to the end and destroy the iceberg, that is pretty much it. For example, the goal of Learn to Fly is to take out the iceberg that is several thousand yards away. On the other hand, there are some games on the playlist that have very defined endings. There isn’t really a defined ending, but it will take you a long time to get to a point where progression gets very slow and boring. For example, Tiny Fishing has players progressively catching more and more fish that increase in value.
Many idle games just have players going from stage to stage, slowly leveling up.