doctorbadwolf
Heretic of The Seventh Circle
Not really. Anyone can learn to fix simple stuff on their car. But even ignoring home repair, you gotta have mechanics. A lot of them. It has to be a normal working class job.Again, I don't think the 70% number is necessary. 70% of people in the early industrial era--or now--don't know how to program or build mechanical constructs. We all know how to use an iPhone, turn on a light, etc, but that's not the equivalent of spell-casting. I can imagine a "magical-industrial" era in which there are magic guilds which control the means of production, but create devices--from glowing orbs to trains to sending stones--that everyone is able to use. In major devices you might need a spell-caster to keep something running or in control, but in everyday objects you don't need them.
But it really depends upon what you want--the ubiquity of magic, what can be created, and how closely you feel you need to align with the RAW. I'm just saying that it is possible to build a plausible magical-industrial world in which only a small number of people are spell-casters.
If teleportation replaces trains and cars...you need thousands upon thousands of mages casting the spell, or at least thousands of mages making teleportation circles that anyone can use. Are you gonna posit that 1 mage is making dozens of types of magitech conveniences? Even if so, mage ends up needing to be a regular middle class job for that to be common enough to be comparable to industrialization.