This is an interesting situation, especially with magic having high costs on the user. To use an analogy, its situation were a single person could construct a building and wreck themselves in the process, or a large group of people could build the same building with less risk. The only difference from our world is that, in your setting, the building gets erected in the exact same amount of time either way.
Historically speaking, humans have been more or less fine with endangering themselves if it meant getting more profit (see any dangerous but high paying profession) and the march of technology was slow until the printing press revolutionized education. Doing things the magic way and damn-the-human-cost might be a common practice in your world.
Of course, then you have the problem that the same people who are being exploited for profit and the ones who have the means to resist exploition.
"Phil, I'm going to need you to turn this water into Chianti, in the process lowering your lifespan or maybe permanently raising your blood pressure, while I take most of the profit."
"Actually, boss, how about I take the entire profit and, in return, not transform 50% of you into a frog. Thanks for the magic classes, by the way."
Then again, a profession that carries a high amount of risk, demands a large amount of training, has the potential to generate a lot of profit, and would be a stupid thing to teach lower-lass people to do already existed in our world. They were/are called warriors, people skilled in combat.
Consequently, your magicians/wizards would likely be in charge or employed by people who are in charge. After all, if they are both finite and powerful, why waste them plowing fields when they can be used to secure land and resources or deter invaders with just their presence? Let the peasants invent plows, aqueducts, and roadways. We need the magic users in the kings army.
Sorry I turned your mages into WMDs. I get excited whenever magic gets presented as finite commodities.