The Moonies are stuck in limbo, unable to die, consumed by boredom
The gems are not in limbo. They are able to die, but not naturally. Without an enemy they would be consumed by the same kind of boredom.
Th Admirabilis are mortal and thus they are the closest to humanity, despite being, as far as we know, only one aspect of humanity as a whole. They are if not independent, then at least less affected by the kind of karmic cycle that the moonies definitely suffer from, and the gems might be suffering from. They reproduce and they die. They have the possibility to inherit the world.
The whole situation reminds me of Lord of the Rings in a way. The gift of man, or one aspect of it at least, was Eru giving mankind natural mortality. This gave men (and hobbits) the impetus and initiative to shape their own future. Unlike the elves whose entire being, both physical and spiritual, was inextricably bound to the creation, the gift of man also meant that their spirits were freed from that creation, and granted freedom. They are the masters of their own lives, as opposed to the elves whose fate was linked to the fate of Arda, and thus lacked any real agency of their own