Isn't this basically Entropy? Why do stars fuse and spread out their energy? Can't they just keep it all in? They are going to blow up/die out eventually, how is this sustainable?

The notion I'm getting is that these forces that drive change are bigger than all of us, and they are inherently unsustainable in the larger scale of things, pretty similar to how solar systems are not really sustainable in a scale much larger than us, but not that is still pretty small in a universal scale.

So for your perspective it might be unsustainable, but for the bigger system what you describe is smaller than a grain of sand.