There are bits and pieces scattered throughout the books about magi who believe that the original Realm, or Eden, was the Magic Realm. That got me to thinking of how that could have come about.
The Premise
Eden, the original Realm, was the Magic Realm with any Empyreal (Dominion) Eden forming later.
The Idea
The Faerie Realm formed when powerful beings of the Magic Realm started to interact directly with the mundane realm, with humans specifically. The Dominion formed when a Demiurge of Magic, probably a Kosmokrator-level Spirit, decided to interact directly with the mundane realm and each successive Demiurge of Magic ever since has slowly sapped the vitality of the Magic Realm, which is why ancient rituals like those that give The Gift have ceased to work. The Infernal Realm formed when Faeries actively opposed the Demiurges of Magic.
The Implication
This is why in most Dominion Lore, the end of days comes about during a reckoning which puts the entire cosmos under the rule of the Dominion, e.g. the Second Coming will involve a new Demiurge of Magic that will convert all the other Realms into the Dominion.
Sounds like a very cool heresy! Hermetic Heretics FTW! I can see a sect of magi (nor necessarily a mystery cult, but you can take that path if you want) preaching that message subtly in the tractatus they circulate and the conversations they have with other magical practitioners and covenfolk.
it is an interesting theory, I have my own ideas based on ancient Sumerian mythology (because of course I do) but the idea of faerie arising after magic seems almost intrinsic in that faerie is dependent upon humans where magic is not. How dominion and infernal fit into the cosmology is another whole issue... dominion could be seen as simply faeries who decided to harness the idea of belief instead of simply possibility and stories...
I have long thought this to was roughly how things should actually have worked, since the divine seems so dependent on belief and actions and just as with faerie, the belief in the story makes it true.