Another hypothesis I have involves an aspect of the magic in the MH universe. P mentions that magic seems to be weaker in places that have the internet. I think having introduced the internet to the Labyrinth will have related consequence in weakening the magic (and maybe freeing Asterion?). I don't think it's the internet in itself that weakens the magic but more the knowledge that it brings. The true power of magic is the lack of knowledge in how the universe works and the belief in that the universe works by magic is what powers magic. As more people become knowledgeable in how the world works, it leads to people becoming less superstitious and weakens magic. This is what eventually happened to the Greek gods, for all their power people stopped worshipping and believing in them that they lost power and faded away. Having a few people (Argos for example) isn't enough to keep the gods in power but it is enough to keep them alive in a way. This also makes me wonder if Argos is actually keeping the hotel alive by praying and worshipping the gods and keeping their power alive. It could one other reason why he had the Master act pious to gods that they clearly don't believe in. If the gods disappear completely, so to does their last ounce of power and presence, like the Labyrinth.