The Introduction of magic into a D&D Economy

[Oracle_Hunter]

But its only 1 in 30 for ANY form of magic, so if you do the math there is only a one in 150 chance of each base magic class

But you really only need a small town to get 2 casters of the same type to really take off. They can "research" spells independently and then share them with each other. I suppose with Clerics it doesn't matter, but as soon as a Wizard finds a buddy, their potential knowledge begins to explode.