Like I said, the Dannans are made from concepts. The loss of concepts takes a heavy toll on the world, but its not as if the world ends without them. The lifespan of the world becomes greatly reduced and magic and sacred power vanishes eventually due to the lack of Dannans to maintain singularity in those concepts, but the world lives on, albeit in a decrepit state. The world pushes for a new Dannan pantheon because with Dannans existing, concepts can be consolidated and centalised around a Dannan born from that particular concept. Its not absolutely necessary, but it is much, much better if they do exist. If what you say is correct, then HwaRan should not have become a Dannan at the end, since her Jiangshi phisiology allows her to channel Demonic energy; but we all know how that goes. 

Like I said, a Dannan is not necessary, but having one is a boon. They help the world function better and the world is worse off without them, but their existence is not necessary for the world to exist. If that was the case, the world should have ended when the Titans were slain, since unlike Dannans, the Titans were literal embodiments of the primodial essence of the world.

There are no miracles. The Danans are born from concepts, and as ancient beings, they can influence those concepts. Erin Danua, the Dannan of Justice, can influence the rollout of justice and can win against any odds as long as the party she is defending is just. Tatez Balthazar is the opposite. He can fuel his concept with his own thirst for vengance and can further enhance it theough the others' thirst for vengance. The land doesn't need them to prosper. They have been technically non-existent for thousands of years at this point, and the land is moving on without them. True, their power do help with many things, but the world does not "need" them at all. If anything, the world is better off without them and their nemeses,the Demons. The skirmishes between Dannans and Demons caused much destruction during the post-Titan era before the Giodel War. If you don't know the lore, don't say things that contradict it.

Dannans were not gods to begin with. In fact, this world has no g**, or gods, whatsoever. The Titans were the first to walk on the land, then the Titan's tyrannical regime were toppled by the lesser Dannans who valued coexistence and wanted lesser races to have better chances. The Dannans were later killed off in war by a sheer numbers advantage by the Giodels who were the ancestors of humans. That's what.

Or a g**, which he becomes at the end.

pretty much