Draconic enchanto-consumption theory
The theory of draconic-enchanto-consumption is a controversial theory pioneered by Synergetics expert Professor Gorr in 1325 AE. Its main thrust is that the Elder Dragons are actually consuming the magic of the world "at an alarming rate," in an apparent contravention of the Seventh Law of Maginamics. This would mean that, unlike what was previously thought, magic is in fact a finite resource.
The Durmand Priory believes that this knowledge will cause a cultural revolution, however in fact the Arcane Council has known of this phenomenon for some time, and had planned on keeping it secret until they'd figured out a way of utilising it for the sole benefit of Rata Sum. To this end, the Arcane Eye were ordered to dispatch Gorr, but the assassination attempt (and a subsequent kidnapping) were foiled by the Orders of Tyria.
After the Battle of Claw Island resulted in Risen forces led by Blightghast the Plaguebringer taking Claw Island, Gorr developed the Vacuumagic Polarizer, a rifle that essentially removes the magic from a person or object, poisons it, and then transfers it back. Similar technology was used aboard the Glory of Tyria, and was instrumental in the defeat of Zhaitan.
In 1327 AE, Scarlet Briar awakened the Elder Dragon Mordremoth by disrupting a major ley line beneath Sanctum Harbor. How exactly this caused the Elder Dragon to stir, long before it should have, is not yet clear.
Tests on dragon minions have shown that dragons do in fact absorb magic, and that the amount of power and self-determination that a dragon minion has is proportional to the amount of energy imbued in it by its Elder Dragon master. However, in these initial tests the minions did not spontaneously consume magic, but were forced to absorb it. Low-level dragon minions, it seem, do not consume, but only destroy.
The theory was given more solid proof during the Pact offensive in Orr, where Mouths of Zhaitan, powerful dragon champions, were seen literally eating magical artifacts that had been hoarded by lesser minions. Mouths are rarely seen and Zhaitan let out a roar when one was killed, so it can be assumed that there were not many of them.