Here's the thing about magic versus technology:
Both are essentially similar. They involve using the natural laws to achieve a desired effect. The magic in use is part of that, but it's something that only experienced casters can do. This is where it differs from technology:
Where technology is concerned, you have several people: You have the inventors who create ideas, engineers who make the ideas workable, manufacturing plants to make the workable plans into a reality, and then you have the finished product. Where magic is concerned, you have a number of known spells that can be manipulated and laws to manipulate them with, but no matter how powerful the spell you come up with is, it's still a spell. A magic wand is not a gun; guns can be mass-produced, but a wizard has to spend XP to make a wand, and even that requires a specialist who knows what he's doing to operate it. After that, it can't be recharged, you need to make a completely new one. You could mass-produce wizards in theory, but this requires you to find specific specimens and indoctrinate them on the ways of the arcane, which takes years to do. Even then, only the cream of the crop can be high-level wizards. In my campaign world, a general rule I use is that, out of a large population, 80% are infrastructure (laborers, farmers, merchants, etc.), and 10% of the remainder are wizards. Half are first- level; for every level up, the number decreases by 50%. So in a whole big world with half a billion people (mass society never really comes into play, no population boom), that makes 10 million wizards total, but only 9 or 10 at 20th level. Wizards above 12th-level, however, number in the thousands.