There’s two primary types of magic in fantasy novels. The personal kind, in which a wizard casts a spell himself, usually completing it within a few seconds of starting. It can have stunning effects, but it’s rarely very complex. Then there’s ritual magic, which involves a group of wizards combining their efforts, casting for a long time (usually at least minutes, sometimes hours or days), and often involving significant material components or sacrifices. The results can be almost anything, and are usually game changing.
Industry seems to me to be ritual magic that we humans can actually do. A few extremely knowledgeable wizards develop the ritual aspects of the spell – what actions must be taken, what order they must be taken in, how often they must be repeated. They determine what material components will be needed to invoke the powers of the beyond, and how they are to be manipulated by the casting wizards. Then they invest a great deal of time, money, and energy into bringing all the required elements to a single place. After this they train support wizards in the casting of the spell, assigning a role to each, and watch as the world is altered to match their will.
This level of magic is extremely powerful. One such ritual can create a large device – big enough for a man to sit in with plenty of room left for carrying physical goods. It can move this man, as well as many hundreds of pounds of material, for hundreds of miles at speeds faster than the swiftest horse. It does so without tiring, needing only occasional stops to refuel. It protects the man in a cage of steel, keeps the air at a comfortable temperature around him, and plays music for him to keep him entertained. There is not a single wizard of those who cast the ritual that could have made this device on his own in even a year’s time. Yet when combined with others to multiply their magic, they can produce one such device per wizard every three days! They can produce them so reliably and affordably that nearly every family owns one of their own. Many own several.
Imagine what could be done in a world where everyone was a wizard, and the majority of the population spent ~40 hours a week casting ritual magic. They would never need starve. They could see nearly anywhere, and speak with nearly anyone, at any time. They could travel to other worlds.
Joseph Campbell (allegedly) said “The priests used to say that faith can move mountains, and nobody believed them. Today the scientists say that they can level mountains, and nobody doubts them.”