Industrialisation in a fantasy setting should come around a lot sooner. In fact, where a lot of stories put you, there should already be some analogue to factories, if magic is easy enough to use that someone with an interest could magic together the prerequisite systems to do so. Population growth and QoL should be high too, since even if it's not possible to have wizardy herberts taking care of everyone, they should be able to expend a fraction of the required effort into facilitating the mass-production of food and useful products. Increasing the fertility of soil and the growth of plants, creating enchanted furnaces and metal casts and conveyor belts and so on for tools and vital equipment...
If things are still as shit as in medieval Europe, then people with magic are unreasonably selfish pricks.
Or they understand their own power base and seek to protect it (which to be fair, is not mutually exclusive with being selfish pricks, just unreasonable ones
). Or it's, say, extraordinarily rare. It also depends on how magic works, whether it's amenable to the scientific method or widespread use. For instance, if the power for magic is "conserved" (and I use the word loosely, understand) by draining, say, some hypothetical life force or prana out of the surroundings, the widespread use of magic may be understood also to mean the death of fertile life in the area (purveyors of environmentalist aesops, rejoice), or if magic runs off the
wielder's life force, mages may wonder why they should cut time off their life to give someone a bit of air conditioning. I also recall a somewhat old sci-fi story (back when psionics was still a serious thing in sci-fi) where a world literally had magic, with the consequence that it never developed anything vaguely resembling the scientific method, precisely because this world's "magic" was a function of will rather than
reality known scientific law; one of the mouthpiece characters in the story actually asks
the audience the other character how can you develop a coherent theory about electricity when you can make the current run from negative to positive, positive to negative, or hold perfectly still regardless of voltage gradient simply by thinking it to be so, and how can you ensure reproducibility when the results of any subsequent experiments by other people are entirely dependent on the experimenter being in a similar frame of mind as you and amenable to your conclusions.
It's important to remember that not all magic in fiction is the same, and so a certain set of assumptions must be made. For instance, the most amenable environment for a Magindustrial Revolution would be a world with a magic system ruled by a logical and rigorous system subject to scientific inquiry that is also spread sufficiently among the population, either by natural aptitude, potential for tutelage in the arts, and/or by use of intermediary objects such as artifacts or wands usable by the uninducted, and also without immediate or obvious severe costs (for instance, coal-firing does have a huge environmental cost, but not one immediately obvious to a pre-industrial population). D&D is a great example, bringing us the Tippyverse and other shenanigans. Discworld is another one. Valdemar in the Mage Storms trilogy was beginning to hint at becoming a third, though the stories when taken in chronological order in-'verse don't reach the point where things like djinn-powered combustion engines really take off.
Great-- Now, imagine the "magical device landfill".
Isn't that actually the title of a Pratchett short story?
EDIT: Corrected a blip there. Also, I can't believe I explicitly mentioned D&D and the Tippyverse while completely forgetting about the canon magical-industrial lands of Netheril and Eberron until Bohandas brought it up below. Huge mea culpa, there. >_<